Article

Factor Analysis of the Mystical Experience Questionnaire: A Study of Experiences Occasioned by the Hallucinogen Psilocybin

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

A large body of historical evidence describes the use of hallucinogenic compounds, such as psilocybin mushrooms, for religious purposes. But few scientific studies have attempted to measure or characterize hallucinogen-occasioned spiritual experiences. The present study examined the factor structure of the Mystical Experience Questionnaire (MEQ), a self-report measure that has been used to assess the effects of hallucinogens in laboratory studies. Participants (N=1602) completed the 43-item MEQ in reference to a mystical or profound experience they had had after ingesting psilocybin. Exploratory factor analysis of the MEQ retained 30 items and revealed a 4-factor structure covering the dimensions of classic mystical experience: unity, noetic quality, sacredness (F1); positive mood (F2); transcendence of time/space (F3); and ineffability (F4). MEQ factor scores showed good internal reliability and correlated with the Hood Mysticism Scale, indicating convergent validity. Participants who endorsed having had a mystical experience on psilocybin, compared to those who did not, had significantly higher factor scores, indicating construct validity. The 4-factor structure was confirmed in a second sample (N=440) and demonstrated superior fit compared to alternative models. The results provide initial evidence of the validity, reliability, and factor structure of a 30-item scale for measuring single, hallucinogen-occasioned mystical experiences, which may be a useful tool in the scientific study of mysticism.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... Initial characterizations of MEs suggested -within the variety of MEs -either a mysticism of introspection or of unifying vision (Otto, 1932). Indeed, MEs alter some key aspects of consciousness, such as the sense of time and space (Hood, 1975;James, 1902;Newberg and d'Aquili, 2008;MacLean et al., 2012). In addition, if they are induced by psilocybin, they also encompass the dimensions of sacredness and positive moods (MacLean et al., 2012). ...
... Indeed, MEs alter some key aspects of consciousness, such as the sense of time and space (Hood, 1975;James, 1902;Newberg and d'Aquili, 2008;MacLean et al., 2012). In addition, if they are induced by psilocybin, they also encompass the dimensions of sacredness and positive moods (MacLean et al., 2012). For instance, Stace (1960) stated that an ultimate unity "is the very essence of all mystical experiences" (p. ...
... These controlled drug experiences, similar to mystical ones, incorporated the dimensions of unity, sacredness, positive mood, transcendence of time/space, ineffability (MacLean et al., 2012), and of being overwhelming both cognitively and emotionally. Like MEs, these states could be emotionally ambivalent, as they could involve not only positive emotions but also regret, fear, anxiety, and upset (Brown et al., 2019). ...
Full-text available
Article
The concept of transformative experience (TE) has been widely explored by several disciplines from philosophy to neurobiology, and in different domains, from the spiritual to the educational one. This attitude has engendered heterogeneous models to explain this phenomenon. However, a consistent and clear understanding of this construct remains elusive. The aim of this work is to provide an initial comprehensive interdisciplinary, cross-domain, up-to-date, and integrated overview on the concept of TEs. Firstly, all the models and theories on TEs were reviewed to extract and analyze TEs’ main components emerging from different disciplines. Then, this preliminary analysis was integrated with an in-depth examination of redundancies and particularities across domains and disciplines, to provide an integrated theoretical framework of TEs and a preliminary interdisciplinary operational definition of TEs. This examination, in turn, can help organize current research and theories, thus providing suggestions for operationalizing TEs as well as encouraging new interdisciplinary research endeavors.
... The MEQ Barrett, Johnson, and Griffiths 2015;Bouso et al. 2016bBouso et al. , 2017MacLean et al. 2012;Schenberg et al. 2017) was developed in the mid-1960s in the United States to evaluate the mystical experience induced by psilocybin (Pahnke 1969(Pahnke , 1963. The scale is theoretically based on the hypothesis that the experience of a spiritual or mystical experience is common and comparable to different cultures, with the experience of unity at the heart of all mystical experiences (Pahnke 1963;Stace 1960). ...
... Subsequently, Bouso et al. (2016b) translated it into Spanish and explored the psychometric properties of the scale with data acquired from participants shortly after ayahuasca ceremonies. No satisfactory evidence was found for the four factors proposed by MacLean et al. (2012) and Barrett, Johnson, and Griffiths (2015) using CFA, but two other factors were proposed using EFA (Bouso et al. 2016b). The scale was also translated and validated for Brazilian Portuguese through an electronic survey sample with people who used several psychedelics, confirming the four factors proposed by MacLean et al. (2012) through CFA (Schenberg et al. 2017). ...
... No satisfactory evidence was found for the four factors proposed by MacLean et al. (2012) and Barrett, Johnson, and Griffiths (2015) using CFA, but two other factors were proposed using EFA (Bouso et al. 2016b). The scale was also translated and validated for Brazilian Portuguese through an electronic survey sample with people who used several psychedelics, confirming the four factors proposed by MacLean et al. (2012) through CFA (Schenberg et al. 2017). ...
Article
There has been a revival of research that studies the subjective effects of psychedelic drugs on humans. Areas of health science have been studying their possible therapeutic benefits, and psychological measurement instruments are being developed as the studies progress. However, these instruments currently suffer criticism regarding their number and evidence of psychometric quality. This study aims to review which psychometric instruments are available to assess subjective states induced by psychedelics. We systematically searched five databases (Web of Science, Academic Search Premier, EMBASE, CINAHL and PubMed) using psychometrics and psychedelics related terms identifying studies published from 1990 to 2021. Of 857 articles generated from the systematic-search, fifteen met our criteria and were included in the review, evaluating nine instruments: MEQ, 5D-ASC, HRS, PSI, EDI, CEQ, EBI, EDI and PIQ. Eight dealing with phenomenological aspects of the psychedelic experience and one as a screening tool for psychotic or manic episode. The purpose of each instrument, the number of items in each version, the type of scale and their elaboration process were described. The number of instruments used in psychedelic research is growing steadily, but there are still many other parts of the psychedelic experience that lack measurement.
... Based on this definition, a questionnaire (the Pahnke-Richards Mystical Experience Questionnaire) was developed to measure mystical experiences triggered by psilocybin (Doblin 1991;Griffiths et al. 2006). Later, an adapted version (i.e., the MEQ30) was psychometrically validated with data from an online survey (Maclean et al. 2012) and clinical studies with psilocybin (Barrett, Johnson, and Griffiths 2015). ...
... The purpose was to determine which factor structure would show the best fit. The first possible factor structure was the four factors model (i.e., with mystical, positive mood, transcendence, and ineffability factors) obtained with previous factor analyses on the original (Barrett, Johnson, and Griffiths 2015;Maclean et al. 2012) and a Finnish version (Kangaslampi, Hausen, and Rauteenmaa 2020) of the MEQ30. The second possible factor structure (the Hood model) was a three factors model (i.e., introvertive, extrovertive, and interpretation factors) based on the Hood Mysticism Scale (Hood 1975). ...
... Regarding construct validity, results showed that the French MEQ30 has the same four-factor structure as the English (Barrett, Johnson, and Griffiths 2015;Maclean et al. 2012) and Finnish (Kangaslampi, Hausen, and Rauteenmaa 2020) versions, with factors corresponding to the mystical, positive mood, transcendence of time and space, and ineffability dimensions of mystical experiences as defined by Stace (Barrett and Griffiths 2018;Johnson et al. 2019). Moreover, internal consistency was good to excellent for the total score and subscores of the French MEQ30. ...
Article
Mystical experiences triggered by psychedelic drugs predict symptom reduction in various psychiatric disorders, and increased well-being in healthy individuals. This work aimed at validating a French version of a tool used to measure mystical experiences: the Revised Mystical Experience Questionnaire-30 items (MEQ30). Construct validity, internal consistencies, concurrent, discriminant, and predictive validities of the French MEQ30 were examined using data about the most significant psychedelic experience of 320 French individuals. Results showed that the original four-factor (i.e., mystical, positive mood, transcendence, and ineffability) structure fit the data best, with good to excellent statistical indices. Total French MEQ30 score was strongly associated with subjective ratings of the mystical (i.e., mystical, spiritual, or religious, and personally significant) and drug intensity-related qualities of the experience, but not with non-mystical (i.e., fun, inebriating, and easy) qualities. Moreover, French MEQ30 score was a significant predictor of subjective positive changes in psychological well-being, relations with self and others, feeling of proximity or connection with nature, and creativity, whereas drug intensity-related and non-mystical qualities of the experience were not, or were only weakly associated with such changes. This French version of the MEQ30 seems to be an appropriate tool for measuring mystical experiences among French speaking individuals.
... Mystical states were measured using The Revised Mystical Experience Questionnaire (MEQ30) [59], a 30-item measure developed from the MEQ43 [60]. The MEQ30 includes 4 subscales: mystical, positive mood, transcendence of time and space, and ineffability. ...
... Scores range from 0 to 150 with higher scores reflecting higher mystical experiences. The MEQ30 has good reliability for all 4 subscales [59,60]. Internal consistency for the current study was excellent (α = 0.97). ...
Full-text available
Article
Chanting is practiced in many religious and secular traditions and involves rhythmic vocalization or mental repetition of a sound or phrase. This study examined how chanting relates to cognitive function, altered states, and quality of life across a wide range of traditions. A global survey was used to assess experiences during chanting including flow states, mystical experiences, mindfulness, and mind wandering. Further, attributes of chanting were assessed to determine their association with altered states and cognitive benefits, and whether psychological correlates of chanting are associated with quality of life. Responses were analyzed from 456 English speaking participants who regularly chant across 32 countries and various chanting traditions. Results revealed that different aspects of chanting were associated with distinctive experiential outcomes. Stronger intentionality (devotion, intention, sound) and higher chanting engagement (experience, practice duration, regularity) were associated with altered states and cognitive benefits. Participants whose main practice was call and response chanting reported higher scores of mystical experiences. Participants whose main practice was repetitive prayer reported lower mind wandering. Lastly, intentionality and engagement were associated with quality of life indirectly through altered states and cognitive benefits. This research sheds new light on the phenomenology and psychological consequences of chanting across a range of practices and traditions.
... Some questionnaires that measure the acute psychedelic experience include emotional, social and spiritual aspects of connectedness MacLean et al. 2012;Roseman et al. 2019;Yaden et al. 2019), but there are no measures to capture the multidimensional connectedness which may be felt in the weeks after a psychedelic experience and thus no tools to measure when this state begins to fade. The Watts Connectedness Scale (WCS) has been developed to enable measurement, with a single tool, of 'connectedness to self, others and world' in daily life, before and after any intervention which might be hypothesized to improve it, including psychedelic therapy. ...
... We evaluated construct validity of the WCS by correlating WCS total and subscale scores with scores on related measures and tested postdictive criterion validity using measures of the spiritual, emotional and social components of the acute psychedelic experience. Specifically, the Mystical Experience Questionnaire (MEQ) (MacLean et al. 2012;Pahnke and Richards 1966), Emotional Breakthrough Inventory (EBI) (Roseman et al. 2019) and Communitas Scale were examined as predictors of changes in connectedness pre-vs post-psychedelic. We also evaluated sensitivity to change of the WCS in a randomised controlled trial that compared psilocybinassisted therapy with the same therapy protocol delivered without the psilocybin, and with 6 weeks of daily escitalopram (an SSRI antidepressant medication). ...
Full-text available
Article
Rationale A general feeling of disconnection has been associated with mental and emotional suffering. Improvements to a sense of connectedness to self, others and the wider world have been reported by participants in clinical trials of psychedelic therapy. Such accounts have led us to a definition of the psychological construct of ‘connectedness’ as ‘a state of feeling connected to self, others and the wider world’. Existing tools for measuring connectedness have focused on particular aspects of connectedness, such as ‘social connectedness’ or ‘nature connectedness’, which we hypothesise to be different expressions of a common factor of connectedness. Here, we sought to develop a new scale to measure connectedness as a construct with these multiple domains. We hypothesised that (1) our scale would measure three separable subscale factors pertaining to a felt connection to ‘self’, ‘others’ and ‘world’ and (2) improvements in total and subscale WCS scores would correlate with improved mental health outcomes post psychedelic use. Objectives To validate and test the ‘Watts Connectedness Scale’ (WCS). Methods Psychometric validation of the WCS was carried out using data from three independent studies. Firstly, we pooled data from two prospective observational online survey studies. The WCS was completed before and after a planned psychedelic experience. The total sample of completers from the online surveys was N = 1226. Exploratory and confirmatory factor analysis were performed, and construct and criterion validity were tested. A third dataset was derived from a double-blind randomised controlled trial (RCT) comparing psilocybin-assisted therapy (n = 27) with 6 weeks of daily escitalopram (n = 25) for major depressive disorder (MDD), where the WCS was completed at baseline and at a 6-week primary endpoint. Results As hypothesised, factor analysis of all WCS items revealed three main factors with good internal consistency. WCS showed good construct validity. Significant post-psychedelic increases were observed for total connectedness scores (η2 = 0.339, p < 0.0001), as well as on each of its subscales (p < 0.0001). Acute measures of ‘mystical experience’, ‘emotional breakthrough’, and ‘communitas’ correlated positively with post-psychedelic changes in connectedness (r = 0.42, r = 0.38, r = 0.42, respectively, p < 0.0001). In the RCT, psilocybin therapy was associated with greater increases in WCS scores compared with the escitalopram arm (ηp2 = 0.133, p = 0.009). Conclusions The WCS is a new 3-dimensional index of felt connectedness that may sensitively measure therapeutically relevant psychological changes post-psychedelic use. We believe that the operational definition of connectedness captured by the WCS may have broad relevance in mental health research.
... Over the past decades, a number of questionnaires have been designed with different purposes and different methodological backgrounds to assess the subjective experience during ASC [e.g. [6][7][8][9][10][11][12][13][14][15][16]. While some aim to identify a common phenomenological pattern to provide profiles of differently induced ASC, others focus on a specific phenomenon that is typically associated with a certain means of induction. ...
... To test the construct validity of CEQ and EDI, we included a set of items taken from related questionnaires: the State-Trait Anxiety Inventory (STAI) that comprises two scales to assess episodic as well as dispositional anxiety [23,24], the Altered States of Consciousness Rating Scale (5DASC) that is used to characterize differently induced ASC experiences and covers pleasant experiences of oneness as well as unpleasant effects such as separation from oneself and the world [10,11], the 30-item Mystical Experience Questionnaire (MEQ30) that measures different aspects of mystical-type experiences [13,14,25], and the Phenomenology of Consciousness Inventory (PCI) [7,8,26] that was designed to quantify patterns of the subjective experience during mostly non-pharmacologically induced ASC. ...
Full-text available
Article
Several measures have been designed to assess subjective experiences induced by psychedelic substances or other mind-altering drugs as well as non-pharmacological methods. Recently, two self-report questionnaires have been introduced to measure acute adverse effects following psilocybin ingestion and the phenomenon of ego-dissolution associated with the use of psychedelics, respectively. The 26-item Challenging Experience Questionnaire assesses multiple facets of psilocybin induced experiences on seven subscales, whereas the 8-item Ego-Dissolution Inventory consists of a unidimensional scale. In the present study, these questionnaires were translated into German and their psychometric properties then evaluated in an online survey on psychedelics induced experiences. Confirmatory factor analysis suggested an acceptable fit of the 7-factor structure of the German Challenging Experience Questionnaire with overall good internal consistency for all subscales. The factor structure did not differ based on gender or prior struggle with a psychiatric disorder, furthering the evidence of internal validity. Correlations with the State-Trait-Anxiety Inventory and the Altered States of Consciousness Rating Scale demonstrated convergent validity. Confirmatory factor analysis did not support the hypothesized single-factor structure of the German Ego-Dissolution Inventory and exploratory factor analysis suggested an alternative factor structure, where only five items loaded onto a common factor that was interpreted as ego-dissolution. Internal consistency of this 5-item measure was high and correlation with selected items of the Mystical Experience Questionnaire and Altered States of Consciousness Rating Scale supported convergent validity. Translation and validation of these questionnaires contribute to the advancement of common standards in the psychological and neuroscientific study of altered states of consciousness.
... Although the nature of the ME remains enigmatic, researchers have managed to identify certain phenomenological characteristics, or dimensions, of those experiences that resonate with the majority of participants . These include: the sense of awe, unity and sacredness; timelessness and spacelessness; ineffability; as well as a sense of authenticity and validity of the reality that is being witnessed, despite its unrecognizable, sometimes even bizarre makeup (Hood, 2001;MacLean et al., 2012). ...
... This has been attributed to lasting changes in functional connectivity between brain regions responsible for attention and self-awareness (e.g., between the right insula and the prefrontal cortex) that seem to be the result of mindfulness practice (Farb et al., 2007;Hasenkamp and Barsalou, 2012). More experienced meditators are also more likely to experience ego dissolution, which is a hallmark of high dose psychedelic experiences (Hölzel and Ott, 2006;MacLean et al., 2012). What is more, practicing the ability to attain an ASC seems to be translational across different techniques. ...
Full-text available
Article
Psychotherapy with the use of psychedelic substances, including psilocybin, lysergic acid diethylamide (LSD), ketamine, and 3,4-methylenedioxymethamphetamine (MDMA), has demonstrated promise in treatment of post-traumatic stress disorder (PTSD), anxiety, addiction, and treatment-resistant depression. Psychedelic-assisted psychotherapy (PP) represents a unique psychopharmacological model that leverages the profound effects of the psychedelic experience. That experience is characterized by strong dependency on two key factors: participant mindset and the therapeutic environment. As such, therapeutic models that utilize psychedelics reflect the need for careful design that promotes an open, flexible, trusting mindset and a supportive setting. To meet this need, the PP model is increasingly supplemented by auxiliary methods, including meditation, relaxation, visualization or spiritual practices. We suggest virtual reality (VR) as a full-spectrum tool able to capitalize on and catalyze the innately therapeutic aspects of the psychedelic experience, such as detachment from familiar reality, alteration of self-experience, augmentation of sensory perception and induction of mystical-type experiences. This is facilitated by VR’s evidenced capacity to: aid relaxation and reduce anxiety; buffer from external stimuli; promote a mindful presence; train the mind to achieve altered states of consciousness (ASC); evoke mystical states; enhance therapeutic alliance and encourage self-efficacy. While these unique VR features appear promising, VR’s potential role in PP remains speculative due to lack of empirical evidence on the combined use of VR and PP. Given the increased commercial interest in this synergy there is an urgent need to evaluate this approach. We suggest specific VR models and their role within PP protocols to inspire future direction in scientific research, and provide a list of potential disadvantages, side effects and limitations that need to be carefully considered. These include sensory overstimulation, cyber-sickness, triggering memories of past traumatic events as well as distracting from the inner experience or strongly influencing its contents. A balanced, evidence-based approach may provide continuity across all phases of treatment, support transition into and out of an ASC, deepen acute ASC experiences including mystical states and enrich the psychotherapeutic process of integration. We conclude that the potential application of VR in modulating psychedelic-assisted psychotherapy demands further exploration and an evidence-based approach to both design and implementation.
... Mystical experiences are often said to feature a perception of unity with everything, feelings of sacredness, the experience of truth at a fundamental level, positive mood, transcendence of time/space and ineffability. These features can be measured through self-reported psychometric scales (Barrett and Griffiths 2018;Maclean et al. 2012;Stace 1960). ...
... A questionnaire derived from the State of Consciousness Questionnaire (SOCQ), developed to assess the occurrence of a mystical-type experience (Barrett and Griffiths 2018;Pahnke 1963Pahnke , 1969b. Its most recent version is a 30-item questionnaire with a four-factor structure (mystical, positive mood, transcendence of time/space and ineffability), although it may vary according to the population studied (Barrett et al. 2015;Maclean et al. 2012). The MEQ30 has been validated for the Brazilian population with its original four-factor structure: mystical, positive mood, transcendence of time/space and ineffability (Schenberg et al. 2017). ...
Full-text available
Article
Rationale Smoking-related disease is a major problem globally. Effective smoking cessation treatments are however limited. Increasing evidence suggests that psychedelics have potential as treatments for substance use disorders and may therefore prove an option in aiding smoking cessation. Objectives To establish which factors predict smoking cessation in people who reported quitting or reducing smoking following ayahuasca consumption. Methods A retrospective cross-sectional mixed-method study (quantitative and qualitative design) was undertaken using data from an online survey evaluating peoples’ experiences before and after drinking ayahuasca. Multivariate logistic regression was performed with smoking condition (cessation or reduction/relapse) as a dependent variable and demographics, smoking, ayahuasca-related variables and the mystical experience (MEQ30) as predicting factors. Results A total of 441 responses were grouped according to self-reported smoking status: cessation (n = 305) or reduction/relapse (n = 136) smoking. Logistic regression showed that mystical experience (OR: 1.03; 95% CI [1.00–1.05]) and frequency of ayahuasca intake (OR: 2.16[1.00–4.70]) were protective factors, while positive mood (measured by the MEQ30) during the ayahuasca experience was a risk factor (OR: 0.91[0.85–0.97]). Qualitative thematic analysis identified eight themes (e.g. acquired awareness, spiritual experience, increased motivation) related to the ayahuasca experience and the process of smoking cessation/reduction. Conclusions Our results suggest that ayahuasca could be used as a potential tool for smoking cessation, and that effects may be mediated by mystical experience. Given the current burden of smoking-related disease and the limited treatment options, studies are needed to investigate the efficacy of psychedelics in smoking cessation.
... The Mystical Experience Questionnaire (MEQ; MacLean et al., 2012), originally derived from the States of Consciousness Questionnaire (SOCQ; Griffiths et al., 2006;Pahnke, 1963), was devised to capture specific qualities of the psychedelic peak experience, including subscales related to 'Mystical', 'Transcendence of Time and Space', 'Positive Mood ' and 'Ineffability' (MacLean et al., 2012). Consistently, the psychedelic peak experience -as measured using the MEQ and related dimensions of the 5-and 11-dimensional Altered States of Consciousness Questionnaire (5D-ASC, Dittrich et al., 2010;11D-ASC, Studerus et al., 2010) -has been associated with enduring positive outcomes in both healthy groups and patient populations (Davis et al., 2020a;Garcia-Romeu et al., 2019b;Griffiths et al., 2008;Roseman et al., 2019). ...
... In the same way that the present study found a relationship between emotional breakthrough and psychological insight (of the personal type), there may be a parallel relationship between unitive experiences (e.g. as indexed by the MEQ) and this more transpersonal, philosophical type of insight. This hypothesis could be tested in future studies by using either existing (Hanley et al., 2018;MacLean et al., 2012) or new measures of the unitive experience, as well as a new measure of transpersonal insight or shifting high-level (e.g. metaphysical) beliefs or perspectives. ...
Full-text available
Article
Introduction As their name suggests, ‘psychedelic’ (mind-revealing) compounds are thought to catalyse processes of psychological insight; however, few satisfactory scales exist to sample this. This study sought to develop a new scale to measure psychological insight after a psychedelic experience: the Psychological Insight Scale (PIS). Methods The PIS is a six- to seven-item questionnaire that enquires about psychological insight after a psychedelic experience (PIS-6) and accompanied behavioural changes (PIS item 7). In total, 886 participants took part in a study in which the PIS and other questionnaires were completed in a prospective fashion in relation to a planned psychedelic experience. For validation purposes, data from 279 participants were analysed from a non-specific ‘global psychedelic survey’ study. Results Principal components analysis of PIS scores revealed a principal component explaining 73.57% of the variance, which displayed high internal consistency at multiple timepoints throughout the study (average Cronbach’s α = 0.94). Criterion validity was confirmed using the global psychedelic survey study, and convergent validity was confirmed via the Therapeutic-Realizations Scale. Furthermore, PIS scores significantly mediated the relationship between emotional breakthrough and long-term well-being. Conclusion The PIS is complementary to current subjective measures used in psychedelic studies, most of which are completed in relation to the acute experience. Insight – as measured by the PIS – was found to be a key mediator of long-term psychological outcomes following a psychedelic experience. Future research may investigate how insight varies throughout a psychedelic process, its underlying neurobiology and how it impacts behaviour and mental health.
... While several measures of the acute classic psychedelic experience show promise as predictors of long-term outcomes (e.g. Mystical Experience Questionnaire, 9,10 Ego Dissolution Inventory, 11,12 and Challenging Experience Questionnaire 13,14 ), recent research suggests that psychological insight may be a common feature of the classic psychedelic experience and particularly important for therapeutic efficacy. 7,15,16 There are currently two self-report measures of psychological insight that have been used in research on classic psychedelics. ...
Full-text available
Article
Background Preliminary evidence suggests that classic psychedelics may be effective in the treatment of some psychiatric disorders, yet little remains known about their effects on health behavior and physical health. Objectives The purpose of this study was to investigate associations of lifetime classic psychedelic use and psychological insight during one’s most insightful classic psychedelic experience with health behavior and physical health. Methods Using data representative of the US population with regard to sex, age, and ethnicity ( N = 2822), this study examined associations of lifetime classic psychedelic use and psychological insight with health behavior and physical health. Results Lifetime classic psychedelic use was associated with more healthy tobacco-related and diet-related behavior ( β = 0.05 and 0.09, respectively). Among lifetime classic psychedelic users ( n = 613), greater Psychological Insight Questionnaire (PIQ) total scale, PIQ Avoidance and Maladaptive Patterns (AMP) subscale, and PIQ Goals and Adaptive Patterns (GAP) subscale scores were each associated with higher odds of more healthy exercise-related behavior [adjusted odds ratios (aOR) (95% confidence interval, CI = 1.38 (1.13–1.68), 1.38 (1.13–1.68), and 1.32 (1.10–1.60), respectively] and higher odds of having a healthy body mass index (BMI) [aOR (95% CI) = 1.32 (1.07–1.63), 1.36 (1.10–1.69), and 1.23 (1.01–1.50), respectively], and greater GAP subscale scores were associated with more healthy diet-related behavior ( β = 0.10). All PIQ scales were positively associated with some health behavior improvements (overall, diet, exercise) attributed to respondents’ most insightful classic psychedelic experience ( β = 0.42, 0.18, and 0.17; β = 0.40, 0.19, and 0.17; and β = 0.40, 0.15, and 0.15, respectively), but only PIQ total scale and AMP subscale scores were positively associated with alcohol-related health behavior improvements ( β = 0.13 and 0.16, respectively). Conclusion Although these results cannot demonstrate causality, they suggest that psychological insight during a classic psychedelic experience may lead to positive health behavior change and better physical health in some domains, in particular in those related to weight management.
... Psychedelic research has long recognized a spiritual component that results from large dose experiences, which is termed mysticism or transcendence in much of the literature (Pahnke, 1969;Williams, 2016). Mystical or transcendent experiences from psychedelics promote personal meaning and correspond with positive long-term change Maclean et al., 2012). The comprehensive lens of social work practice is congruent with the wide-reaching layers of the psychedelic experience. ...
Full-text available
Research
Breakthrough therapy designations, newfound funding opportunities, and research-supported efficacy are pointing to psychedelic-assisted therapies as promising treatments now and in the future. While this expansion is multidisciplinary in nature, the social work profession has been largely removed from the research and application of these treatments even though they provide the majority of behavioral services and have historically responded favorable to medication-assisted modalities. In lieu of no prior studies, this study investigates the knowledge, attitudes, influences, and professional response of social workers towards psychedelic-assisted treatments. Semi-structured interviews were conducted with fifteen participants following a chain recruitment model. Content and thematic analysis led to the findings of this study. The analysis found limited knowledge among participants. The study also found that past experiences, including one’s use/non-use of psychedelics, geographic residency, and personal connectivity to certain diagnoses, impact participants’ attitudes towards these treatments. Ultimately, the study concluded that while safety concerns and stigma are inherent to their perspectives, participants agree that psychedelic-assisted therapies align with the ethical standards of the social work profession. The findings of this study are not generalizable due to the qualitative case study research design; however, the findings do lead to important implications for the field of social work relating to educational curricula, practice guidelines, language and stigma, advocacy, and ethical decision-making, which are discussed. Keywords: psychedelic, psychedelic-assisted treatments, social worker, social work practice, knowledge, attitudes, professional response, ethical standards
... The Altered States of Consciousness [ASC] questionnaire is one of the most widely used instruments for the measurement of alterations of subjective experience (Dittrich, 1998;Studerus et al., 2010;Preller and Vollenweider, 2016). Importantly, the ASC questionnaire spans a variety of dimensions of subjective experience, including both low-level sensory and high-level cognitive components; other questionnaires, such as the Mystical Experience Questionnaire [MEQ] (MacLean et al., 2012;Barrett et al., 2015), do not allow a direct comparison between these different dimensions, since they focus on a singular construct. Clinical studies employing the ASC have shown that high-level dimensions of experience provide good predictions for therapeutic outcomes, better so than low-level dimensions . ...
Full-text available
Article
Psychedelics are undergoing a major resurgence of scientific and clinical interest. While multiple theories and frameworks have been proposed, there is yet no universal agreement on the mechanisms underlying the complex effects of psychedelics on subjective experience and brain dynamics, nor their therapeutic benefits. Despite being prominent in psychedelic phenomenology and distinct from those elicited by other classes of hallucinogens, the effects of psychedelics on low-level sensory - particularly visual - dimensions of experience, and corresponding brain dynamics, have often been disregarded by contemporary research as 'epiphenomenal byproducts'. Here, we review available evidence from neuroimaging, pharmacology, questionnaires, and clinical studies; we propose extensions to existing models, provide testable hypotheses for the potential therapeutic roles of psychedelic-induced visual hallucinations, and simulations of visual phenomena relying on low-level cortical dynamics. In sum, we show that psychedelic-induced alterations in low-level sensory dimensions 1) are unlikely to be entirely causally reconducible to high-level alterations, but rather co-occur with them in a dialogical interplay, and 2) are likely to play a causally relevant role in determining high-level alterations and therapeutic outcomes. We conclude that reevaluating the currently underappreciated role of sensory dimensions in psychedelic states will be highly valuable for neuroscience and clinical practice, and that integrating low-level and domain-specific aspects of psychedelic effects into existing nonspecific models is a necessary step to further understand how these substances effect both acute and long-term change in the human brain.
... In contrast to other agents (such as propofol), states of disconnected consciousness (dream-like states) can be induced by ketamine, even under profound behavioral unresponsiveness (as revealed by a significant body of work (Bonhomme et al. 2019)). The questionnaire used here consisted of 83 items related to 13 subscales (perceptual dimensions), namely: experiences of unity, spiritual experience, blissful state, insightfulness, disembodiment, impaired control and cognition, anxiety, complex imagery, elementary imagery, audio-visual synaesthesia, changed meaning of percepts, transcendence of time and space, and ineffability (further definitions can be found in the original study and in (Studerus, Gamma and Vollenweider 2010;MacLean et al. 2012)). The response for all items was from 0 (no, not more than usual) to 10 (yes, very much more than usual), with the subscale score being the average of all items within that scale. ...
Full-text available
Thesis
Neuroscience has made a number of advances in the search for the neural correlates of consciousness, but our understanding of the neurophysiological markers remains incomplete. In this work, we apply deep learning techniques to resting-state electroencephalographic (EEG) measures of healthy participants under general anesthesia, for the investigation and estimation of altered states of consciousness. Specifically, we focus on states characterized by different levels of unconsciousness and anesthetic depths, based on definitions and metrics from contemporary clinical practice. Our experiments begin by exploring the ability of deep learning to extract relevant electrophysiological features, under a cross-subject decoding task. As there is no state-of-theart model for EEG analysis, we compare two widely used deep learning architectures - convolutional neural networks (cNNs) and multilayer perceptrons (MLPs) - and show that cNNs perform effectively, using only one second of the raw EEG signals. Relying on cNNs, we derive a novel 3D architecture design and a standard preprocessing pipeline, which allows us to exploit the spatio-temporal structure of the EEG, as well as to integrate different acquisition systems and datasets under a common methodology. We then focus on the nature of different predictive tasks, by investigating classification and regression algorithms under a variety of clinical ground-truths, based on behavioral, pharmacological, and psychometrical evidence for consciousness. Our findings provide several insights regarding the interaction across the anesthetic states, the electrophysiological signatures, and the temporal dynamics of the models. We also reveal an optimal training strategy, based on which we can detect progressive changes in levels of unconsciousness, with higher granularity than current clinical methods. Finally, we test the generalizability of our deep learning-based EEG framework, across subjects, experimental designs, and anesthetic agents (propofol, ketamine and xenon). Our results highlight the capacity of our model to acquire appropriate, task-related, cross-study features, and the potential to discover common cross-drug features of unconsciousness. This work has broader significance for discovering generalized electrophysiological markers that index states of consciousness, using a data-driven analysis approach. It also provides a basis for the development of automated, machine-learning driven, non-invasive EEG systems for real-time monitoring of the depth of anesthesia, which can advance patients' comfort and safety.
... Acute subjective effects of psychedelics have been measured in experimental studies using the hallucinogen rating scale (Strassman et al., 1994), the mystical experiences questionnaire (Maclean et al., 2012), and the abnormal mental states questionnaire, renamed the altered states of consciousness rating scale (OAV) (Studerus et al., 2010) and revised as the 5 dimensions of altered states of consciousness scale (5D-ASC) (Dittrich, 1998). This scale includes three primary dimensions: oceanic boundlessness or positively felt ego dissolution, dread of ego dissolution or negatively felt ego dissolution, and visionary restructuralization or visual alterations and altered meaning of precepts. ...
Full-text available
Article
Neuroimaging studies of psychedelics have advanced our understanding of hierarchical brain organization and the mechanisms underlying their subjective and therapeutic effects. The primary mechanism of action of classic psychedelics is binding to serotonergic 5-HT2A receptors. Agonist activity at these receptors leads to neuromodulatory changes in synaptic efficacy that can have a profound effect on hierarchical message-passing in the brain. Here, we review the cognitive and neuroimaging evidence for the effects of psychedelics: in particular, their influence on selfhood and subject-object boundaries—known as ego dissolution—surmised to underwrite their subjective and therapeutic effects. Agonism of 5-HT2A recep-tors, located at the apex of the cortical hierarchy, may have a particularly powerful effect on sentience and consciousness. These effects can endure well after the pharmacological half-life, suggesting that psychedelics may have effects on neural plasticity that may play a role in their therapeutic efficacy. Psychologi-cally, this may be accompanied by a disarming of ego resistance that increases the repertoire of perceptual hypotheses and affords alternate pathways for thought and behavior, including those that undergird selfhood. We consider the interaction between serotonergic neuromodulation and sentience through the lens of hierarchical predictive coding, which speaks to the value of psychedelics in understanding how we make sense of the world and specific predictions about effective connectivity in cortical hierarchies that can be tested using functional neuroimaging. Significance Statement——Classic psychedelics bind to serotonergic 5-HT2A receptors. Their agonist activity at these receptors leads to neuromodulatory changes in synaptic efficacy, resulting in a profound effect on information processing in the brain. Here, we synthesize an abundance of brain imaging research with pharmacological and psychological interpretations informed by the framework of predictive coding. Moreover, predictive coding is suggested to offer more sophisticated interpretations of neuroimaging find-ings by bridging the role between the 5-HT2A receptors and large-scale brain networks.
... We refer interested readers to the pioneering work of Stace (1960) in helping to identify and define this construct. In the present discussion, we focus on the conceptualization provided by the Four Factors in the Mystical Experience Questionnaire (MEQ30) (Maclean et al., 2012;Barrett et al., 2015), which identifies a Mystical Factor (1)-comprised of senses of Internal Unity, External Unity, Noetic Quality, and Sacredness-Positive Mood Factor (2), Transcendence of Time and Space Factor (3), and Ineffability Factor (4). When these factors are present to a sufficient degree (e.g. ...
Full-text available
Preprint
Here we consider psychedelics with respect to their mechanisms of action, use, and implications for our understandings of brain and mind. This review is somewhat nontraditional in its scope, with discussions of both basic facts as well as theoretical speculations. We chose this approach given the unique historical context we find ourselves in at present. While we have decades of investigations to draw upon with respect to the clinical science and neuropsychopharmacology of psychedelics, we are also witnessing a renaissance (or perhaps a revolution) in which scientific and public interest in these compounds seems to be exploding. We have decided to split this review between the fundamental and theoretical, with hopes that we can give readers familiarity with well-established knowledge, as well as questions to hold in mind in attempting to make sense of a rapidly shifting epistemic landscape. Below we focus on serotonin 2A receptor (5-HT2aR) agonists, or “classic psychedelics,” and discuss research suggesting their potential roles in clinical and non-clinical contexts. Particular emphasis is placed on studies suggesting potentially surprising degrees of efficacy for conditions such as depression and addictive disorders. We also evaluate potential mediators and moderators of therapeutic outcomes, including factors such as mystical experiences and psychological flexibility. Finally, we consider likely future directions for psychedelics in science and society.
... The subjective characteristics of the acute experience and overall life changes attributed to the experience were assessed with the Hallucinogen Rating Scale (HRS) [41], selected items from the States of Consciousness Questionnaire [42], the Persisting Effects Questionnaire [42], and the Mystical Experience Questionnaire (MEQ30) [1,43]. A single questionnaire item asked "During your experience, did you encounter something that someone might call "God" (e.g., the God of your understanding), with response option being yes or no. ...
Full-text available
Article
Both psychedelic drug experiences and near-death experiences can occasion changes in perspectives on death and dying, but there have been few direct comparisons of these phenomena. This study directly compared psychedelic occasioned and non-drug experiences which altered individuals’ beliefs about death. Individuals who reported an experience that altered their beliefs about death occasioned by either a psychedelic drug or a near-death or other non-ordinary experience completed an online survey. Circumstances of the experience, mystical and near-death subjective features, changes in attitudes about death, and other persisting effects were evaluated. The study sample ( n = 3192) included five groups: non-drug near-death or other non-ordinary experiences ( n = 933), and drug experiences occasioned by lysergic acid diethylamide (LSD) ( n = 904), psilocybin ( n = 766), ayahuasca ( n = 282), or N , N- dimethyltryptamine (DMT) ( n = 307). Analyses of differences in experiences were adjusted statistically for demographic differences between groups. Compared to the psychedelic groups, the non-drug group was more likely to report being unconscious, clinically dead, and that their life was in imminent danger. The groups were remarkably similar in the reported changes in death attitudes attributed to the experience, including a reduced fear of death and high ratings of positive persisting effects and personal meaning, spiritual significance, and psychological insight. Although both psychedelic and non-drug participants showed robust increases on standardized measures of mystical and near-death experiences, these measures were significantly greater in the psychedelic participants. Non-drug participants were more likely to rate their experiences as the single most meaningful of their lives. Comparing across psychedelic substances, ayahuasca and DMT groups tended report stronger and more positive enduring consequences of the experience than the psilocybin and LSD groups, which were largely indistinguishable. These data provide a detailed characterization and comparison of psychedelic occasioned and non-drug experiences that changed attitudes about death and suggest the importance of future prospective psychedelic administration studies.
... For example, Griffiths et al. (2006) showed that 22 of 36 people who used psilocybin in controlled settings experienced feelings of oneness and transcendence of time and space, but these occurred primarily in people with religious inclinations. Although these investigations mainly use psychometric scales that do not analyze the content of people's religious or mystical belief, they allow an immediate, quantitative, and systematic assessment of the reported experience (e.g., see Barrett, Johnson, and Griffiths 2015;MacLean et al. 2012;Maji c, Schmidt, and Gallinat 2015). Interestingly, it has been shown that the intensity of mystical experiences during the psilocybin effect predicts changes in the "openness" personality trait, which is characterized by imagination, creativity, intellectual flexibility, and sensitivity (MacLean et al. 2011). ...
Full-text available
Article
We present the set and setting of the velada, the Mazatec ritual of divination and healing. We highlight the subjective experiences of individuals who consumed sacred mushrooms and interpret them from their cultural and community contexts, but also from findings derived from experimental and neuroscientific research. We understand that the experiences connected to sacred mushrooms can be explained by the effects of psilocybin on the neurobiology of emotions, decision making, and visual, auditory, and bodily imagery. But we also understand that experimentation does not consider the individual and collective history of the person, and that the velada can provide guidance for integrating a person’s history and beliefs into experimental designs. The resurgence of psychedelic medicine prompts us into a transdisciplinary dialogue that encompasses both the anthropological perspective and the set and setting of the entheogenic experience during the sacred mushroom ritual.
... Following previous recommendations, a MEQ30 total score was used as a measure of participants' mystical experience during the psychedelic experience (Barrett et al., 2015). MacLean et al. (2012) found high internal consistency (α = .93) for the MEQ30, supporting its reliability as a measure of mystical experiences. ...
... Participants then rated three measures related to mindfulness: nowness (feeling of being in present moment), letting go (degree to which person was able to let go of control of the experience), and equanimity (feeling of being in emotional balance). Participants also rated subjective effects derived from the mystical experience questionnaire (MEQ) ( Barrett et al., 2015 ;MacLean et al., 2012 ): pure being and pure awareness, fusion of your personal self into larger whole, sense of reverence or sacredness, timelessness (lack of sense of space/time), ineffability (inability to explain experience with words), feelings of joy, feelings of peace and tranquility. The average score from the MEQ effects was aggregated into a single score to obtain a brief MEQ (bMEQ) score. ...
Article
Background: Classic psychedelics, such as psilocybin and LSD, and other serotonin 2A receptor (5-HT2AR) agonists evoke acute alterations in perception and cognition. Altered thalamocortical connectivity has been hypothesized to underlie these effects, which is supported by some functional MRI (fMRI) studies. These studies have treated the thalamus as a unitary structure, despite known differential 5-HT2AR expression and functional specificity of different intrathalamic nuclei. Independent Component Analysis (ICA) has been previously used to identify reliable group-level functional subdivisions of the thalamus from resting-state fMRI (rsfMRI) data. We build on these efforts with a novel data-maximizing ICA-based approach to examine psilocybin-induced changes in intrathalamic functional organization and thalamocortical connectivity in individual participants. Methods: Baseline rsfMRI data (n=38) from healthy individuals with a long-term meditation practice was utilized to generate a statistical template of thalamic functional subdivisions. This template was then applied in a novel ICA-based analysis of the acute effects of psilocybin on intra- and extra-thalamic functional organization and connectivity in follow-up scans from a subset of the same individuals (n=18). We examined correlations with subjective reports of drug effect and compared with a previously reported analytic approach (treating the thalamus as a single functional unit). Results: Several intrathalamic components showed significant psilocybin-induced alterations in spatial organization, with effects of psilocybin largely localized to the mediodorsal and pulvinar nuclei. The magnitude of changes in individual participants correlated with reported subjective effects. These components demonstrated predominant decreases in thalamocortical connectivity, largely with visual and default mode networks. Analysis in which the thalamus is treated as a singular unitary structure showed an overall numerical increase in thalamocortical connectivity, consistent with previous literature using this approach, but this increase did not reach statistical significance. Conclusions: We utilized a novel analytic approach to discover psilocybin-induced changes in intra- and extra-thalamic functional organization and connectivity of intrathalamic nuclei and cortical networks known to express the 5-HT2AR. These changes were not observed using whole-thalamus analyses, suggesting that psilocybin may cause widespread but modest increases in thalamocortical connectivity that are offset by strong focal decreases in functionally relevant intrathalamic nuclei.
... Although similar questionnaire items (or detailed measures) tend to covary during assessments of mystical experiences, test-retest data can fall short of psychometric standards. A controlled dose that induces mystical reactions at one time is unlikely to create an identical reaction a second time (see MacLean, Leoutsakos, Johnson, & Griffiths, 2012). This variation in responses has inspired centuries of theorizing about set and setting, for example (Hartogsohn, 2017). ...
Full-text available
Article
Mystical experiences frequently precede decreases in human suffering or increased functioning. Therapies that include the ingestion of psychoactive substances in supportive environments often lead to improvements that correlate with the magnitude of the mystical experiences generated. A close look at these phenomena from a philosophy of science perspective might put empiricists in a quandary. Arguments with critics of the import of these mystical experiences, prohibitionists, or others who are apprehensive about psychedelic-assisted treatments, might prove awkward or difficult given the tacit assertion that the mystical genuinely exists. The assumption might even dampen theorizing in ways that remain outside of theorists' awareness. The predicament might lack the epistemic humility ideal for good science as well. Nevertheless, abandoning the construct of mystical experiences would require ignoring compelling, replicated empirical work. We argue that a version of philosophical fictionalism that draws on research in logic and linguistics can help investigators engage in this discourse without implying a belief in the mystical. Comparable approaches have proven helpful in mathematics and empiricism more broadly. Mystical fictionalism could help theorists view reports of mystical experiences as true even if the mystical fails to be veridical. The approach creates an expressive advantage that could assist researchers and theorists eager to refine our understanding of mystical experiences and improve psychedelic-assisted treatments. Mystical fictionalism might also inspire novel looks at correlates of mystical experiences that might serve as mediators of their effects, potentially generating models with comparable explanatory power that sidestep the need for a fictionalist approach.
... The online pre-Isness-D questionnaire (using the survey platform Qualtrics) consisted of the ICS scale 56 and items relating to participants' openness to the upcoming experience. The post-Isness-D questionnaire included: (1) the ICS scale 56 ; 2) the MEQ30 26,27 3) the EDI 84 ; and 4) the Communitas questionnaire 61 . Additionally, participants were asked questions related to bodily effects and demographics. ...
Full-text available
Article
With a growing body of research highlighting the therapeutic potential of experiential phenomenology which diminishes egoic identity and increases one’s sense of connectedness, there is significant interest in how to elicit such ‘self-transcendent experiences’ (STEs) in laboratory contexts. Psychedelic drugs (YDs) have proven particularly effective in this respect, producing subjective phenomenology which reliably elicits intense STEs. With virtual reality (VR) emerging as a powerful tool for constructing new perceptual environments, we describe a VR framework called ‘Isness-distributed’ (Isness-D) which harnesses the unique affordances of distributed multi-person VR to blur conventional self-other boundaries. Within Isness-D, groups of participants co-habit a shared virtual space, collectively experiencing their bodies as luminous energetic essences with diffuse spatial boundaries. It enables moments of ‘energetic coalescence’, a new class of embodied intersubjective experience where bodies can fluidly merge, enabling participants to include multiple others within their self-representation. To evaluate Isness-D, we adopted a citizen science approach, coordinating an international network of Isness-D 'nodes'. We analyzed the results (N = 58) using 4 different self-report scales previously applied to analyze subjective YD phenomenology (the inclusion of community in self scale, ego-dissolution inventory, communitas scale, and the MEQ30 mystical experience questionnaire). Despite the complexities associated with a distributed experiment like this, the Isness-D scores on all 4 scales were statistically indistinguishable from recently published YD studies, demonstrating that distributed VR can be used to design intersubjective STEs where people dissolve their sense of self in the connection to others.
... Small clinical trials over the past 15 years with psilocybin and ayahuasca provide intriguing preliminary evidence for efficacy in treating major depressive disorder (including otherwise treatmentresistant individuals) , 2018Davis et al., 2020;de Osório et al., 2015;Palhano-Fontes et al., 2019), obsessive compulsive disorder (Moreno et al., 2006), smoking addiction (Johnson et al., 2017), alcohol abuse (Bogenschutz et al., 2015), demoralisation (Anderson et al., 2020), and depressive and anxiety symptoms associated with diagnosis of life-threatening diseases (Gasser et al., 2015(Gasser et al., , 2014Griffiths et al., 2016;Grob et al., 2011;Ross et al., 2016). Remarkably, there is also preliminary clinical evidence that psychedelics can produce lasting positive psychological effects in healthy individuals (Barrett et al., 2020a;Griffiths et al., 2011;Kettner et al., 2021;MacLean and Griffiths, 2013;Madsen et al., 2020;Stenbaek et al., 2020;Uthaug et al., 2019Uthaug et al., , 2018. ...
Full-text available
Article
Clinical research into serotonergic psychedelics is expanding rapidly, showing promising efficacy across myriad disorders. Resting-state functional magnetic resonance imaging (rs-fMRI) is a commonly used strategy to identify psychedelic-induced changes in neural pathways in clinical and healthy populations. Here we, a large group of psychedelic imaging researchers, review the 42 research articles published to date, based on the 17 unique studies evaluating psychedelic effects on rs-fMRI, focusing on methodological variation. Prominently, we observe that nearly all studies vary in data processing and analysis methodology, two datasets are the foundation of over half of the published literature, and there is lexical ambiguity in common outcome metric terminology. We offer guidelines for future studies that encourage coherence in the field. Psychedelic rs-fMRI will benefit from the development of novel methods that expand our understanding of the brain mechanisms mediating its intriguing effects; yet, this field is at a crossroads where we must also consider the critical importance of consistency and replicability to effectively converge on stable representations of the neural effects of psychedelics.
... Additionally, outcome expectancies of psychotherapists have been shown to have a marked effect on treatment engagement and clinical outcomes across therapeutic approaches (Doering et al. 2014;Leake and King 1977), suggesting this may be a treatment-nonspecific factor relevant to psychedelic studies as well. Lastly, the specific measures used in psychedelic trials can influence participant expectations; one study volunteer noted "I long to see some of the stuff hinted at in the questionnaire" in reference to questions they encountered on the Mystical Experience Questionnaire (MEQ; MacLean et al. 2012;Pollan 2018). Thus, in addition to preexisting attitudes about psychedelics, certain expectations may be engendered by characteristics of the trial. ...
Full-text available
Article
Rationale Psychedelic research continues to garner significant public and scientific interest with a growing number of clinical studies examining a wide range of conditions and disorders. However, expectancy effects and effective condition masking have been raised as critical limitations to the interpretability of the research. Objective In this article, we review the many methodological challenges of conducting psychedelic clinical trials and provide recommendations for improving the rigor of future research. Results Although some challenges are shared with psychotherapy and pharmacology trials more broadly, psychedelic clinical trials have to contend with several unique sources of potential bias. The subjective effects of a high-dose psychedelic are often so pronounced that it is difficult to mask participants to their treatment condition; the significant hype from positive media coverage on the clinical potential of psychedelics influences participants’ expectations for treatment benefit; and participant unmasking and treatment expectations can interact in such a way that makes psychedelic therapy highly susceptible to large placebo and nocebo effects. Specific recommendations to increase the success of masking procedures and reduce the influence of participant expectancies are discussed in the context of study development, participant recruitment and selection, incomplete disclosure of the study design, choice of active placebo condition, as well as the measurement of participant expectations and masking efficacy. Conclusion Incorporating the recommended design elements is intended to reduce the risk of bias in psychedelic clinical trials and thereby increases the ability to discern treatment-specific effects of psychedelic therapy.
... (1) unity, noetic quality, and sacredness, (2) positive mood, (3) transcendence of time and space, and (4) ineffability (difficulty communicating or describing the experience) (Barrett, Johnson, & Griffiths, 2015;MacLean, Leoutsakos, Johnson, & Griffiths, 2012). ...
Chapter
The past decade has witnessed a rapid growth of research on the basic science and clinical understanding of psychedelics. This chapter provides an overview of the human behavioral pharmacology of psychedelics focusing on three prototypic classic psychedelics—psilocybin, lysergic acid diethylamide (LSD), and dimethyltryptamine (DMT). A brief historical overview of the classic psychedelics and naming and drug classification is first specified. Next, special considerations in the conduct of human behavioral pharmacology work with psychedelics is described including the role of set and setting, mystical experience measurement, the use of effective blinding and placebos, and the abuse liability of psychedelics. Following, a description of the subjective, physiological, and clinical effects of psilocybin, LSD, and DMT is provided. This body of work clearly documents a unique and complex collection of subjective effects following psychedelic use, both during acute drug administration and as related to long-term behavior change following use. Clinical research demonstrates potential therapeutic utility with early phase clinical trials showing positive and enduring effects in many difficult-to-treat conditions including treatment-resistant depression, alcohol use disorder, and cigarette smoking. Future work in this newly reemerged field is needed to reveal mechanisms of behavior change in psychedelic drug action. Behavioral pharmacology is ultimately well served to provide this direction answering questions at the intersection of environment and pharmacology.
... Capturing and quantifying psychedelic experiences and metrics of recovery capital in the setting of psychedelicassisted psychotherapy has proven challenging. The notable personal accounts of enhanced sense of connectedness, spirituality, and meaningfulness that individuals experience during psychedelic-assisted psychotherapy play an important role in improving and sustaining treatment outcomes (Johnson et al., 2017;Nielson et al., 2018;Noorani et al., 2018), and yet remain difficult to measure (Maclean, Leoutsakos, Johnson, & Griffiths, 2012). Furthermore, the emotion awe has been hypothesized to be a key mechanism of action underlying mystical experiences in psychedelicassisted psychotherapy, fostering a sense of connectedness and oneness with others and acting as a principal catalyst for change within the psychedelic-assisted psychotherapy paradigm . ...
Full-text available
Article
Despite growing availability of several evidence-based approaches in the treatment of substance use disorders, existing pharmacotherapy and psychosocial interventions continue to have significant limitations, such as low treatment retention rates and high rates of relapse. There is a need to develop new strategies and models to address these limitations and target underlying psychosocial drivers of addiction, such as motivation to change – a crucial factor in achieving positive addiction treatment outcomes. Re-emerging clinical evidence and literature signal the promise of psychedelic-assisted psychotherapies as being novel, adjunctive treatments for a range of mental health and substance use disorders, encouraging further research. However, there remains a lack of formally validated metrics to evaluate recovery capital and motivation, limiting interpretation of the growing psychedelic literature. This commentary describes the current state of this line of investigation and potential impact of psychedelic-assisted psychotherapy on enhancing motivation to change in addiction treatment, and the need for validated metrics to evaluate recovery motivation and capital to assess the potential for psychedelic-assisted psychotherapies to elicit positive, lasting changes in substance use behaviors among those seeking treatment.
... This stance is known as the "Comforting Delusion Objection" and is discussed and objected to in detail by Letheby (Letheby, 2021). Nevertheless, psychedelic drugs reliably induce the sorts of experiences wherein individuals feel that statements such as "Certainty of encounter with ultimate reality" (MEQ item 9) and "Sense of being at a spiritual height" (MEQ item 15) accurately describe a component of their experience (Griffiths et al., 2006;MacLean et al., 2012;Barrett et al., 2015). As participants feel justified in describing their experiences with such language, the framework of "mystical-type experiences" is a useful one for describing a cluster of co-occurring experiences, independent of ontological judgement of their content, especially given the apparent predictive utility of such experiences. ...
Full-text available
Article
Psychedelic drugs such as psilocybin have shown substantial promise for the treatment of several psychiatric conditions including mood and addictive disorders. They also have the remarkable property of producing persisting positive psychological changes in healthy volunteers for at least several months. In this study (NCT03289949), 35 medium-high doses of psilocybin were administered to 28 healthy volunteers (12 females). By the end of the dosing day, participants reported the intensity of their acute experience using the 30-item Mystical Experience Questionnaire (MEQ) and an open-form qualitative report from home. Persisting psychological effects attributed to the psilocybin experience were measured using the Persisting Effects Questionnaire (PEQ) 3-months after administration. Using a linear latent-variable model we show that the MEQ total score is positively associated with the later emergence of positive PEQ effects ( p = 3 × 10 ⁻⁵ ). Moreover, the MEQ subscales “Positive Mood” ( p corr = 4.1 × 10 ⁻⁴ ) and “Mysticality” ( p corr = 2.0 × 10 ⁻⁴ ) are associated with positive PEQ whereas the subscales “Transcendence of Time and Space” ( p corr = 0.38) and “Ineffability” ( p corr = 0.45) are not. Using natural language pre-processing, we provide the first qualitative descriptions of the “Complete Mystical Experience” induced by orally administered psilocybin in healthy volunteers, revealing themes such as a sense of connection with the Universe, familial love, and the experience of profound beauty. Combining qualitative and quantitative methods, this paper expands understanding of the acute psilocybin induced experience in healthy volunteers and suggests an importance of the type of experience in predicting lasting positive effects.
... For both parts 1 and 2, altered states of consciousness were measured using three questionnaires administered at the end of the day of the drug administration session after dinner: the fivedimensional altered states of consciousness (ASC) scale (Dittrich, 1998), the ego dissolution inventory (EDI; Nour et al., 2016), and the mystical experience questionnaire (MEQ; Barrett et al., 2015;MacLean et al., 2012). All questions were completed on Psytools (Delosis, London) via a laptop computer. ...
Article
Background Classic psychedelics hold promise as therapeutics for psychiatric disorders, but require scalable intervention protocols. This proof-of-concept study evaluated the safety, tolerability, pharmacokinetics, and subjective effects of 50, 75, and 100 µg lysergic acid diethylamide (LSD) in healthy adults within a novel intervention paradigm. Methods Up to three participants were administered LSD on the same day in separate rooms, each with a single attendant, after 1 day of preparation. An open-label design and a double-blind placebo-controlled design were used. Results Ninety-one percent of participants completed the study. Thirty-two adults (mean age = 28.8 years) received 50 (n = 3), 75 (n = 7), 100 (n = 3) LSD, 50 µg followed by 75 µg LSD (n = 9) 1 week apart, or placebo followed by a 75 µg LSD (n = 10) 1 week apart. There were no serious adverse events. Twenty-eight percent of participants experienced at least one expected mild adverse event, with one expected moderate adverse event. The maximum blood plasma levels occurred between 1.2 and 2 h post-administration, with an apparent half-life between 2.8 and 4.3 h. LSD largely induced greater subjective effects versus placebo. Conclusion In the current novel intervention paradigm, 50, 75, and 100 µg LSD are tolerable with favourable safety profiles in healthy adults, only mild adverse events during the day of drug administration, and mystical-type subjective experiences. Future studies are needed to evaluate safety, tolerability, subjective effects, and cost-effectiveness in clinical populations.
... Especially when complementary aspects of interest can be assumed to interact, as is the case with ACE and AVE, focusing on certain types of experiences without considering their interplay with complementary aspects may lead to simplistic representations of their therapeutic value and/or potential harms. In this regard, it is important to note that not only the EBI and the CEQ, but also many other self-report instruments that are used for retrospective characterization of psychedelic experiences, including measures of "oceanic boundlessness" (Studerus et al., 2010), "ego-dissolution" (Nour et al., 2016), "mystical experience" (MacLean et al., 2012), and "psychological insight" use unipolar response formats (e.g. a visual analogue scale with the endpoints "no, not at all" and "extremely"). This format is suited for capturing a given aspect irrespective of potential complementary aspects which may have occurred over the course of the same experience but are missed unless they are captured by an additional complementary scale. ...
Full-text available
Article
Background: Many benefits and some harms associated with psychedelic use could be attributable to these drugs’ acceptance/avoidance-promoting effects and corresponding changes in psychological flexibility. Underlying psychological mechanisms are insufficiently understood. Aim: The purpose of this study was the validation of a psychological model of acceptance/avoidance-promoting psychedelic experiences, which included the development of a theory-based self-report instrument: the Acceptance/Avoidance-Promoting Experiences Questionnaire (APEQ). Its two main scales, acceptance-related experience (ACE) and avoidance-related experience (AVE), represent the theorized model’s core constructs. We aimed to test the model’s central assumptions of complementarity (ACE and AVE may occur alternatingly but not simultaneously, and are therefore empirically independent), intertwinedness (subaspects within ACE and AVE are mutually contingent and therefore highly inter-correlated), context-dependence (ACE and AVE depend on context factors) and interaction (longer-term outcomes depend on the interplay between ACE and AVE). Method: A bilingual retrospective online survey including 997 English- and 836 German-speaking participants. Each participant reported on one psychedelic experience occasioned by lysergic acid diethylamide (LSD), psilocybin, mescaline, or ayahuasca. Results: Whereas ACE and AVE were found to be relatively independent aspects of participants’ reported psychedelic experiences (complementarity), their subaspects were mostly distinguishable but strongly correlated among each other (intertwinedness). Therapeutic, escapist, and hedonic use motives were differentially associated with ACE and AVE (context-dependence), which were in turn associated with retrospective changes in psychological flexibility following participants’ reported experiences. The positive association between ACE and increased psychological flexibility was significantly moderated by AVE (interaction). Conclusion: These results provide an initial validation of the APEQ and its underlying theoretical model, suggesting the two can help clarify the psychological mechanisms of psychedelic-induced benefits and harms. Both should be further investigated in prospective-longitudinal and clinical studies.
... Participants then rated three measures related to mindfulness: nowness (feeling of being in present moment), letting go (degree to which person was able to let go of control of the experience), and equanimity (feeling of being in emotional balance). Participants also rated subjective effects derived from the mystical experience questionnaire (MEQ) (Barrett et al., 2015;MacLean et al., 2012): pure being and pure awareness, fusion of your personal self into larger whole, sense of reverence or sacredness, timelessness (lack of sense of space/time), ineffability (inability to explain experience with words), feelings of joy, feelings of peace and tranquility. The average score from the MEQ effects was aggregated into a single score to obtain a brief MEQ (bMEQ) score. ...
Full-text available
Preprint
Background Serotonin 2A receptor (5-HT 2AR ) agonist psychedelics including psilocybin and LSD (“classic” psychedelics) evoke acute alterations in perception and cognition. Altered thalamocortical connectivity has been proposed to underlie these effects, which is supported by some functional MRI (fMRI) studies. Likely due to sample size limitations, these studies have treated the thalamus as a unitary structure, despite known differential 5-HT 2AR expression and functional specificity of different intrathalamic nuclei. Independent Component Analysis (ICA) has been employed to generate functional subdivisions of the thalamus from resting state fMRI (rsfMRI) data. This report utilizes a novel data-sparing ICA approach in order to examine psilocybin-induced changes in intrathalamic functional organization and thalamocortical connectivity. Methods Baseline rsfMRI data (n=38) was utilized to generate a template, which was then applied in a novel ICA-based analysis of the acute effects of psilocybin on intra- and extra-thalamic functional organization and connectivity in a smaller sample (n=18). Correlations with subjective reports of drug effect and comparisons with a previously reported analytic approach (treating the thalamus as a single functional unit) were conducted. Results Several intrathalamic components showed significant psilocybin-induced alterations in intrathalamic spatial organization, largely localized to the mediodorsal and pulvinar nuclei, and correlated with reported subjective effects. These same components demonstrated alterations in thalamocortical connectivity, largely with visual and default mode networks. Analysis in which the thalamus is treated as a singular unitary structure showed an overall numerical increase in thalamocortical connectivity, consistent with previous literature using this approach, but this increase did not reach statistical significance. Conclusions Utilization of a novel analytic approach demonstrated changes in intra- and extra-thalamic functional organization and connectivity of intrathalamic nuclei and cortical networks known to express the 5-HT 2AR . Given that these changes were not observed using whole-thalamus analyses, it seems that psilocybin may cause widespread but modest increases in thalamocortical connectivity that are offset by strong focal decreases in functionally relevant intrathalamic nuclei.
... Participants will be asked to answer the questionnaire while thinking about one specific memory (the one used in the free recall). -Revised Mystical Experience Questionnaire (MEQ30; Maclean et al., 2012): This 30-item scale is designed to assess the mystical characteristics of a specific episode or memory (in this study, a hypnosis, meditation, or SICT episode), across four factors: mystical, positive mood, transcendence of time/ space, and ineffability. -Presence questionnaire (Heck et al., 2021): This 12-item scale has been initially designed to measure the feeling of presence after the use of virtual reality. ...
Full-text available
Article
Introduction A symptom cluster is very common among oncological patients: cancer-related fatigue (CRF), emotional distress, sleep difficulties, pain, and cognitive difficulties. Clinical applications of interventions based on non-ordinary states of consciousness, mostly hypnosis and meditation, are starting to be investigated in oncology settings. They revealed encouraging results in terms of improvements of these symptoms. However, these studies often focused on breast cancer patients, with methodological limitations (e.g., small sample size, no control group, and no follow-up). Another non-ordinary state of consciousness may also have therapeutic applications in oncology: self-induced cognitive trance (SICT). It seems to differ from hypnosis and meditation, as it involves the body more directly. Thus, investigating its clinical applications, along with hypnosis and meditation interventions, could improve available therapeutic options in oncology. This article details the study protocol of a preference-based longitudinal controlled superiority trial aiming to assess the effectiveness of 3 group interventions (hypnosis, meditation, and SICT) to improve oncological patients’ quality of life, and more specifically CRF, emotional distress, sleep, pain, and cognitive difficulties (primary outcomes). Methods and analysis A power analysis required a total sample of 160 patients. Main inclusion criteria are: cancer diagnosis, active treatments completed for less than a year, no practice of hypnosis, meditation, or SICT, and presence of at least one of these four symptoms: fatigue, sleep difficulties, depression, or anxiety. Each participant will choose the intervention in which they want to participate (hypnosis, mindful self-compassion meditation, SICT, or no intervention—control group). To test the effectiveness of the interventions, data will be collected by questionnaires and neurobiological measures and directly from the medical record at four time points: before inclusion in the study (baseline); immediately after the intervention; and at 3- and 12-month follow-up. The longitudinal data in each group will then be measured. Discussion In addition to standard cancer therapies, there is a growing interest from patients in complementary approaches, such as hypnosis, meditation, and SICT. The results of this study will be useful to increase knowledge about short- and long-term effectiveness of 3 group interventions for CRF, emotional distress, sleep, pain, and cognitive difficulties in patients with different cancers. Clinical Trial Registration ClinicalTrials.gov/ (NCT04873661). Retrospectively registered on the 29th of April 2021. url: https://clinicaltrials.gov/ct2/show/NCT04873661
... When the acute effects had subsided, patients freely described their experiences, and responded to three questionnaires: the Hallucinogenic Rating Scale (HRS) (Mizumoto et al. 2011), the Mystical Experience Questionnaire (MEQ) (Maclean et al. 2012), and the Amsterdam Resting State Questionnaire (ARSQ) (Diaz et al. 2013). Psychiatric evaluations during the dosing session showed that patients had slight transient changes in dissociative and psychotomimetic symptoms, and no significant increases in mania-like symptoms. ...
Chapter
Ayahuasca, the vine of the souls in Quechua, is a psychedelic brew with a few formulations that most often include the bark of a liana in the Malpighiaceae family (Banisteriopsis caapi), with leaves from a shrub in the coffee family Rubiaceae (Psychotria viridis). Mixed with water and boiled for hours or days, it produces a brownish-colored liquid with a strong and characteristic taste. Ayahuasca contains the psychedelic tryptamine N,N-Dimethyltryptamine (DMT), and Monoamine Oxidase Inhibitors (MAOi), and in the past few years, it has been tested. In recent years its antidepressant properties have been put to the test. Evidence from open and randomized placebo-controlled clinical trials has shown encouraging results, indicating significant and rapid antidepressant effects, starting as early as 1 day after the ayahuasca intervention. In addition, we have explored the nature of these effects using multivariate measures. In this article, we will review the history, pharmacology, clinical trials, and clinical and behavioral markers associated with the antidepressant effects of ayahuasca.
... Positive or euphoric effects are variously described, and may include loss of sense of self, a sense of timelessness, and feelings of emotional catharsis, forgiveness, or self-compassion (Watts et al. 2017;Studerus et al. 2011;Gasser et al. 2015;Belser et al. 2017). One common scale for quantifying subjective effects is the Mystical Experience Questionnaire (MEQ), which scores four dimensions of a "mystical experience": sacredness, positive mood, transcendence of time/space, and ineffability (Maclean et al. 2012). Other scales used to quantify subjective effects of hallucinogens include the Hallucinogen Rating Scale (HRS), the Five Dimensions-Altered State of Consciousness scale (5D-ASC), and the Challenging Experiences Questionnaire (CEQ) (Strassman et al. 1994;Studerus et al. 2010;Barrett et al. 2016). ...
Full-text available
Article
Rationale A broad reassessment of the potential benefits of psychedelic drugs has led to the initiation of multiple major clinical trials in an effort to advance their status to become FDA-approved medications, as well as local legislative efforts to legalize or decriminalize their use. Objectives To use recently published data to assess potential risks and benefits of psychedelic drugs as therapeutics, as well as to synthesize what is currently known in order to generate fruitful future research directions. Methods A review of studies conducted since 1991 identified 14 clinical trials of classical psychedelics, including 11 of psilocybin (N = 257 participants), 1 of lysergic acid diethylamide (N = 12 participants), and 2 of ayahuasca (N = 46 participants). Other published studies (e.g., of healthy volunteers, survey studies, case reports, neuroimaging) were also considered for review. Results Published studies since 1991 largely support the hypothesis that small numbers of treatments with psychedelic-assisted psychotherapy can offer significant and sustained alleviation to symptoms of multiple psychiatric conditions. No serious adverse events attributed to psychedelic therapy have been reported. Existing studies have several limitations, including small sample sizes, inherent difficulty in blinding, relatively limited follow-up, and highly screened treatment populations. Conclusions Substantial data have been gathered in the past 30 years suggesting that psychedelics are a potent treatment for a variety of common psychiatric conditions, though the ideal means of employing these substances to minimize adverse events and maximize therapeutic effects remains controversial. Unique factors related to study design are vital for clinical researchers in the field to address.
... This stance is known as the "Comforting Delusion Objection" and is discussed and objected to in detail by Letheby (Letheby, 2021). Nevertheless, psychedelic drugs reliably induce the sorts of experiences wherein individuals feel that statements such as "Certainty of encounter with ultimate reality" (MEQ item 9) and "Sense of being at a spiritual height" (MEQ item 15) accurately describe a component of their experience (Griffiths et al., 2006;MacLean et al., 2012;Barrett et al., 2015). As participants feel justified in describing their experiences with such language, the framework of "mystical-type experiences" is a useful one for describing a cluster of co-occurring experiences, independent of ontological judgement of their content, especially given the apparent predictive utility of such experiences. ...
Full-text available
Preprint
Psychedelic drugs such as psilocybin are under investigation for the treatment of several psychiatric conditions. They also have the remarkable property of producing persisting positive psychological changes in healthy volunteers for at least several months. In this study, 35 medium-high doses of psilocybin were administered to 28 healthy volunteers (12 females). By the end of the dosing day, participants reported the intensity of their acute experience using the 30-item Mystical Experience Questionnaire (MEQ) and an open-form qualitative report from home. Persisting psychological effects attributed to the psilocybin experience were measured using the Persisting Effects Questionnaire (PEQ) three-months after administration. Using a linear latent-variable model we show that the MEQ total score is positively associated with the later emergence of positive PEQ effects (p = 3x10-5). Moreover, the MEQ subscales “Positive Mood” (pcorr = 4.1x10-4) and “Mysticality” (pcorr = 2.0x10-4) are associated with positive PEQ whereas the subscales “Transcendence of Time and Space” (pcorr = 0.38) and “Ineffability” (pcorr = 0.45) are not. Using natural language pre-processing, we provide the first qualitative descriptions of the “Complete Mystical Experience” induced by orally administered psilocybin in healthy volunteers, revealing themes such as a sense of connection with the universe, familial love, and the experience of profound beauty. Combining qualitative and quantitative methods, this paper expands understanding of the acute psilocybin induced experience in healthy volunteers and suggests an importance of the type of experience in predicting lasting positive effects.
Article
Investigations of the use of psychedelic or entheogenic drugs in spiritual contexts have focused on mystical experience. Arguing that entheogenic spirituality should be understood more broadly, this study recruited 319 individuals into an online survey. Respondents were predominantly from western countries, but reported a connection to an eclectic range of religious and spiritual traditions, with Buddhism as the largest religion. About half of the respondents reported having a meditation practice, and the most endorsed motivations for entheogen use related to personal growth and spirituality. For spiritually motivated respondents, entheogenic experiences were most commonly characterized by feelings of joy, peace, and love, by insight into oneself and one’s relations, and by improved connections with nature and with other people. Spiritually affiliated participants were more likely to report mystical experiences involving ego dissolution and contact or unity experiences and reported more positive long-term consequences from entheogen use. The study affirms the existence of a movement of spiritually motivated entheogen users that requires further investigation.
Full-text available
Article
In this paper, we present the development of the Altered States Database (ASDB), an open-science project based on a systematic literature review. The ASDB contains psychometric questionnaire data on subjective experiences of altered states of consciousness (ASC) induced by pharmacological and non-pharmacological methods. The systematic review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Scientific journal articles were identified through PubMed and Web of Science. We included studies that examined ASC using the following validated questionnaires: Altered States of Consciousness Rating Scale (APZ, 5D-ASC, 11-ASC), Phenomenology of Consciousness Inventory (PCI), Hallucinogen Rating Scale (HRS), or Mystical Experience Questionnaire (MEQ30). The systematic review resulted in the inclusion of a total of 165 journal articles, whereof questionnaire data was extracted and is now available on the Open Science Framework (OSF) website (https://osf.io/8mbru) and on the ASDB website (http://alteredstatesdb.org), where questionnaire data can be easily retrieved and visualized. This data allows the calculation of comparable psychometric values of ASC experiences and of dose-response relationships of substances inducing ASC.
Full-text available
Preprint
Lysergic acid diethylamide (LSD) is a potent classic serotonergic psychedelic, which facilitates a variety of altered states of consciousness. Here we present the first meta-analysis establishing dose-response relationship estimates of the phenomenological states induced by LSD. Data extracted from articles identified by a systematic literature search following PRISMA guidelines were obtained from the Altered States Database. The psychometric data comprised ratings of subjective effects from standardized and validated questionnaires: the Altered States of Consciousness Rating Scale (5D-ASC, 11-ASC) and the Mystical Experience Questionnaire (MEQ30). We used a meta-regression approach to obtain estimates for linear dose-response relationships of questionnaire ratings after LSD administration to healthy, highly selected study participants in controlled settings for a dosage range between 25 μg and 200 μg. LSD doses positively correlated with ratings on most factors and scales of the questionnaires, with strongest responses for visionary phenomena such as audio-visual synesthesia and altered imagery, followed by positively perceived ego dissolution comprising depersonalization and derealization phenomena. Measures referring to mystical experiences exhibited weak modulations by dose. The established dose-response relationships in the given range may be used as general references for future experimental and clinical research on LSD with low to moderate dosages to relate observed with expected subjective effects and to elucidate phenomenological differences between psychedelics.
Full-text available
Article
Background: Naturalistic and placebo-controlled studies suggest ayahuasca, a potent psychedelic beverage originating from Indigenous Amazonian tradition, may improve mental health, alter personality structure, and reduce alcohol and drug intake. To better understand ayahuasca’s therapeutic potential and to identify factors that influence therapeutic efficacy, we conducted a naturalistic, longitudinal study of facilitated ayahuasca consumption in naïve participants using a comprehensive battery of self-report questionnaires. Materials and Methods: Ayahuasca naive individuals registering for ayahuasca ceremonies were asked to complete a range of validated questionnaires assessing mental health, alcohol/cannabis use, relationships, personality, and connection to self and spirituality, prior to and 1 month after attending an ayahuasca ceremony. Data for two mental health measures (the DASS-21 and PANAS) and acute subjective effects via the MEQ-30 were also assessed 7 days post-ceremony. Repeated measures ANOVA were used to examine pre-to-post changes, and Pearson correlations explored predictors of improvement in outcomes. Results: Fifty-three attendees (32 women, 21 men) completed pre and post ayahuasca assessments with 55.6% of the sample reporting a complete mystical experience based on the MEQ-30. One-month post-ayahuasca, significant reductions were identified in depression, anxiety, stress, alcohol and cannabis use, body dissociation, accepting external influence, self-alienation, impulsivity, and negative affect/emotionality. Significant increases were identified in positive mood, self-efficacy, authentic living, extraversion, agreeableness, open-mindedness, spirituality, and satisfaction with relationships. While facets of the mystical experience held little predictive validity on outcome measures, baseline traits, particularly high negative emotionality and body dissociation, and low sense of self-efficacy, robustly predicted improvements in mental health and alcohol/cannabis use, and alterations in personality structure which are linked to better mental health. Discussion: This study suggests facilitated ayahuasca consumption in naïve participants may precipitate wide-ranging improvements in mental health, relationships, personality structure, and alcohol use. Associations between baseline traits and therapeutic improvements mark an important first step toward personalized, precision-based medicine and warrant randomized controlled trials to confirm and elaborate on these findings. Contribution Statement: Longitudinal, observational studies and randomized clinical control trials suggest ayahuasca may exert therapeutic effects on mental health and alcohol/cannabis use, and alter personality structure. However, it is unclear if improvements are diagnosis-specific and factors that predict therapeutic gains have yet to be extensively elucidated. This longitudinal, observational study examined the effects of facilitated ayahuasca consumption in naive participants on mental health, alcohol and substance use/abuse, personality traits, relationships, and connection to self and spirituality. We found wide-ranging improvements 1-month post-treatment across these domains, and identified baseline traits which predict pre-to-post changes on primary outcome measures. Improvements were not diagnostic-specific, suggesting ayahuasca may be generally efficacious. Personality traits, body dissociation, and self-efficacy were strong predictors of therapeutic improvements, marking an important first step toward personalized, precision-based medicine. Randomized controlled trials are warranted to confirm and elaborate on these findings.
Article
There are global concerns about the proliferation and misuse of club drugs and novel psychoactive substances, yet we know little about their harms and research on clinical management and treatment remains limited. This book fills the knowledge gap by providing a detailed overview of the research evidence available to date. The book provides a framework that allows readers to understand this large number of new drugs, using classifications based on primary psychoactive effect. Within this framework, the book provides detailed reviews of the more commonly used drugs. Each chapter explores pharmacology, patterns and mode of use, acute and chronic harms, and clinical interventions supported by research evidence. An invaluable resource for clinical staff, this book will support clinicians working in the emergency department, substance misuse and addiction services, mental health services, primary care, sexual health services and more. It will also be of interest to academics and those developing drug policy.
Full-text available
Article
According to Stocker (in press), seeing in visual experience (visual perception and visual imagery) is organized by Talmyan concept structuring. Here, it is proposed that during seeing in extrovertive visionary experience and extrovertive mystical experience, this visual concept structuring is largely or totally suspended—except for the perspective point ( pp ), which seems to remain in place in all human seeing. Complemented with cognitive-semantic analysis, characterizations of extrovertive visionary experience draw from the writer and philosopher Aldous Huxley, and characterizations of extrovertive mystical experience additionally from the theologian Rudolph Otto and the philosopher Walter Stace. It is also examined how well extrovertive visionary experience and extrovertive mystical experience are captured with altered-state-of-consciousness questionnaires. Potential benefits for the mind from temporary suspension of Talmyan concept structuring are discussed.
Article
Background Clinical studies report preliminary therapeutic effects of classic psychedelic drugs in several psychiatric conditions and international drug trends show increased use of these compounds. However, the epidemiology of classic psychedelic drug use in Scandinavian countries remains sparsely investigated. To this end, we investigated the patterns of use and the subjectively perceived acute and persisting effects of lysergic acid diethylamide (LSD), psilocybin, N,N-dimethyltryptamine (DMT), and mescaline, among Danish adults. Methods An anonymous online survey with 152 items was conducted using the secure survey web application REDCap. Results were presented descriptively and as comparisons between psychedelic drugs. Results Five-hundred participants (30.0% female, mean age 34.5 years) were included. Classic psychedelics were mostly used with therapeutic (28.0%) or spiritual (27.2%) intentions. Sixty-seven per cent used classic psychedelics once a year or less. Most participants (56.4%) preferred using psilocybin. Classic psychedelic use was for some individuals, associated with hazardous use of alcohol (39.4%). Among participants with a psychiatric treatment history, 80.9% reported subjective improvements in symptoms following classic psychedelic use. Participants’ most memorable experiences were moderate-to-strong mystical-type experiences (MEQ30 mean ± SD 3.4 ± 1.0; range 1–5) and had positive persisting effects on well-being (mean ± SD 2.1 ± 1.0), social relationships (mean ± SD 1.7 ± 1.2), meaning of life (mean ± SD 1.9 ± 1.1), and mood (mean ± SD 1.8 ± 1.1); range −3 to 3. DMT users experienced significantly greater subjective positive effects. Conclusions Classic psychedelics were mostly used therapeutically or spiritually and had self-reported positive persisting effects, but were also associated with hazardous use of alcohol, among Danish adults. DMT was associated with significantly greater positive effects compared to LSD and psilocybin.
Article
Subjective responses to psychoactive drugs have served as intriguing windows into consciousness as well as useful predictors. Subjective reactions to psychedelic molecules are particularly interesting given how they covary with subsequent improvements associated with psychedelic-assisted treatments. Although links between subjective reactions and decreases in treatment-resistant clinical depression, end-of-life anxiety, and maladaptive consumption of alcohol and nicotine appear in the empirical literature, the measurement of these subjective responses has proven difficult. Several scales developed over many decades show reasonable internal consistency. Studies suggest that many have a replicable factor structure and other good psychometric properties, but samples are often small and self-selected. We review the psychometric properties of some of the most widely used scales and detail their links to improvement in response to psychedelic-assisted treatments. Generally, assessments of mystical experiences or oceanic boundlessness correlate with improvements. Challenging subjective experiences, psychological insight, and emotional breakthroughs also show considerable promise, though replication would strengthen conclusions. We suggest a collaborative approach where investigators can focus on key responses to ensure that the field will eventually have data from many participants who report their subjective reactions to psychedelic molecules in a therapeutic setting. This may aid in predicting improvement amongst targeted conditions and wellbeing.
Article
Expanding on the work of Forstmann and Sagioglou, this study investigated the differences in personality and pro-environmental behavior (PEB) as a function of psychedelic-occasioned mystical experiences. A sample of 240 participants with prior psychedelic experience completed an online survey. Data were collected on participants’ psychedelic-occasioned mystical states, personality, and self-reported PEB. A measure of behavioral PEB was also included (Charity Task). The mean scores on self-reported PEB, openness and agreeableness of participants who met the criteria for a “complete” mystical state, were significantly higher than those who did not. Specifically, those who experienced a mystical state scored higher on the PEB types “eco-shopping and eating” and “one-off domestic conservation actions.” Participants who demonstrated PEB in the Charity Task scored higher on self-reported PEB than those who did not, supporting the task’s validity. Findings suggest that mystical experiences influence PEB. Future research with experimental designs could further illuminate potential causal relationships.
Full-text available
Article
Recent studies have recognized the importance of non-pharmacological factors such as setting to induce or promote mystical experiences or challenging experiences among ayahuasca users. This study aimed to evaluate the association between the setting in which ayahuasca is consumed and the intensity of mystical and challenging experiences considering three ayahuasca using traditions (União do Vegetal, Santo Daime and neo-shamanic groups). A cross-sectional analysis was performed on survey data collected online from 2,751 participants. The Setting Questionnaire for the Ayahuasca Experience (SQAE) was used to evaluate six dimensions of the setting characteristics. The Mystical Experience Questionnaire (MEQ) and the Challenging Experience Questionnaire (CEQ) were used to quantify the psychedelic experience. Ratings on every SQAE setting dimension were negatively correlated with ratings of the CEQ (r values between 0.21 and 0.36) for all ayahuasca using traditions. Regression analysis revealed that ratings on four SQAE dimensions (Social, Comfort, Infrastructure and Decoration) explained 41% of the variance in CEQ ratings. Associations between SQAE and MEQ ratings were relatively weak and confined to the dimensions Leadership and Comfort, explaining 14% of the variance in MEQ ratings. Ratings of Social context were higher among members of União do Vegetal compared to Santo Daime and neo-shamanic members. Ratings of Infrastructure, Comfort and Decoration were more consistently correlated with MEQ in the neoshamanic tradition compared to the other traditions. This study shows that the setting is an important moderator of a challenging experience under ayahuasca. Maximizing the quality of the setting in which ayahuasca is taken will reduce the chance of a challenging experience while contributing positively to a mystical experience. The present findings can be considered when designing rituals and the (social) environment of ayahuasca ceremonies, and indicate that the SQAE questionnaire can be employed to monitor the influence of ceremonial settings on the ayahuasca experience.
Full-text available
Article
Background There is currently renewed interest in the use of psychedelic therapy in the treatment of psychiatric disorders, including depression. The proposed systematic review will aim to identify, evaluate and summarise the psychological processes of change underlying psychedelic therapy for depression in the current literature and consider the implications these processes may have on the psychotherapy component of treatment. Methods Scopus, PsycINFO, PubMed and Web of Science databases will be searched using relevant terms. Studies will be included if they discuss the use of a classic psychedelic to treat depression symptomology in an adult population and report or propose psychological processes responsible for depression symptom change. Two authors will independently screen articles, complete quality assessment tools and conduct data extraction. Empirical and non-empirical research will be extracted and synthesised separately. A narrative synthesis approach will be used to report psychological processes identified in the literature. Discussion This systematic review will be the first to collate available evidence on the psychological processes associated with psychedelic therapy for depression. The preliminary nature of this research field is expected to result in the review having several limitations, namely heterogeneity between studies and the inclusion of limited empirical research. We intend for this review to present the current state of the literature, identify gaps and generate candidate variables that warrant further investigation. Systematic review PROSPERO CRD42020197202
Full-text available
Article
The urgent need for solutions to critical environmental challenges is well attested, but often environmental problems are understood as fundamentally collective action problems. However, to solve these problems, there is also a need to change individual behavior. Hence, there is a pressing need to inculcate in individuals the environmental virtues-virtues of character that relate to our environmental place in the world. We propose a way of meeting this need, by the judicious, safe, and controlled administration of "classic" psychedelic drugs as a way to catalyze the development of environmental virtues-a form of moral bio-enhancement. Recent evidence shows that psychedelics can be given safely in controlled environments, and can induce vivid experiences of unity and connectedness. These experiences, in turn, can durably increase feelings of nature-relatedness and pro-environmental behaviors. Therefore, we argue that responsible psychedelic use can reliably catalyze the development of a key environmental virtue known as living in place. This is a "master environmental virtue" that subsumes the qualities of respect for nature, proper humility, and aesthetic wonder and awe. Our account advances the environmental virtues debate by introducing a relevant practical proposal, and advances the psychedelic moral enhancement debate by providing a much-needed conceptual framework.
Full-text available
Thesis
Master's Thesis by Tomko Settgast, supervised by Mathias Hegele and Dominik Endres: The text at hand investigates the possibilities to capture the so-called flow-experience without the reliance on subjective reports, i.e. it follows the intention to explore reliably and objectively measurable markers. This search especially regards neural correlates of the experience in question that have not been found yet. The text is thereby subsumed under the umbrella of enactivism since it gives similar credit to phenomenology and neuroscience, uses the description of the dynamical system’s theory and bridges the phenomenal and natural scientific aspects of cognition via an ecologically psychological sense-making. The introduction of the neurophenomenological method at the beginning of the text offers the possibility to suggest objective markers of subjective experience based on correlation. A central position within thisobjectification is given to the entropic brain hypothesis, as it is prominently represented by Carhart-Harris (2018). Its claim to connect subjective experience to the brain’s dynamically working mechanism enables its linkage to a dynamical system’s account for cognition. The dynamical attractors that the systems theory suggest for guiding behaviour is thereby easily integrated within the notions of predictive coding (i.a. Kilner, Friston, Frith, 2007; Clark, 2015) that assumes predictions to be the foundation of perception. Under the assumption of enactivism and its notion of a unity of perception and action, one gets the opportunity to translate the dynamical system’s attractors with Gibson’s (1986) idea of affordances. Thus, the brain’s dynamical working mechanism is the reflection of the phenomenal experience of affordances that guide perception and action. Especially, skilled action will be explored as the consequence of simultaneously attracting affordances which allow for the use of different strategies in pursuing a goal. This dynamically metastable attunement to different affordances (Bruineberg & Rietveld, 2014) constitutes exactly the entirety of the introduced dynamical attractors and is reflected in the brain activities’ entropy. This hypothesis is completed with the introduction of the serotonin’s and dopamine’s neuromodulation on these attractor-based affordances where those neuromodulator’s influences in perceptual guidance and behavioural selection as well as execution are emphasised. The exploration of these neurophysiological measurements enables the linkage of subjective and objective markers of flow-experience after a flow-experience’s phenomenal characterisation is given. Therefore, the outlined objective measurements are followed by an introduction of flow-experience within the notion of Csíkszentmihályi (1975). Its phenomenal characterisation and the introduced theories are used to suggest an objective measurement of flow-experience. The text uses the similarity between the flow-experience’sphenomenology and the experience of (musical) improvisation to infer a way to investigate ojectively measurable markers of flow. As it will be revealed later, this is based on the fact that the cognitive neuroscience of improvisation leads to a phenomenological experience that is summarised as the creator-witness phenomenon a fter Berkowitz (2010) what will be made fruitful as a way to investigate the state of flow. Taken together, professional musical improvisation as a specific example of skilled action shows a phenomenal proximity to flow-experience wherefore its underlying neural mechanism isinferred as the underlying mechanism of flow-experience. Hence, an objectively measurable marker of theflow’s state of mind will be explored in the increase of the brain activities’ entropy that reflects an increase in themetastable attunement to different but simultaneously visible affordances.
Full-text available
Article
The first objective of this article is to propose a conceptual framework of the effects of on-line questionnaire design on the quality of collected responses. Secondly, we present the results of an experiment where different protocols have been tested and compared in a randomised design using the basis of several quality indexes. Starting from some previous categorizations, and from the main factors identified in the literature, we first propose an initial global framework of the questionnaire and question characteristics in a web survey, divided into five groups of factors. Our framework was built to follow the response process successive stages of the contact between the respondent and the questionnaire itself. Then, because it has been studied in the survey methodology literature in a very restricted way, the concept of ‘response quality’ is discussed and extended with some more ‘qualitative’ criteria that could be helpful for researchers and practitioners, in order to obtain a deeper assessment of the survey output. As an experiment, on the basis of the factors chosen as major characteristics of the questionnaire design, eight versions of a questionnaire related to young people’s consumption patterns were created. The links to these on-line questionnaires were sent in November 2005 to a target of 10,000 young people. The article finally presents the results of our study and discusses the conclusions. Very interesting results come to light; especially regarding the influence of length, interaction and question wording dimensions on response quality. We discuss the effects of Web-questionnaire design characteristics on the quality of data.
Full-text available
Article
The Satisfaction With Life Scale (SWLS) was developed to assess satisfaction with the respondent’s life as a whole. The scale does not assess satisfaction with life domains such as health or finances but allows subjects to integrate and weight these domains in whatever way they choose. Normative data are presented for the scale, which shows good convergent validity with other scales and with other types of assessments of subjective well-being. Life satisfaction as assessed by the SWLS shows a degree of temporal stability (e.g., 54 for 4 years), yet the SWLS has shown sufficient sensitivity to be potentially valuable to detect change in life satisfaction during the course of clinical intervention. Further, the scale shows discriminant validity from emotional well-being measures. The SWLS is recommended as a complement to scales that focus on psychopathology or emotional well-being because it assesses an individuals’ conscious evaluative judgment of his or her life by using the person’s own criteria.
Full-text available
Article
Religious experience is an important but understudied aspect of religion. Sociologists need a theoretical approach that appreciates the existence of and variation in the social distribution of religious experiences. Recognizing that theories are interpretive frameworks through which we view the world, and understanding that ''every way of seeing is a way of not seeing,'' we examine two potential ''ways of seeing'' religious experience in modem society and explore their ability co shed light upon recent surveys which suggest that as much as half the United States adult population has had what can be called ''religious experiences. '' As the dominant views in sociology largely exclude from consideration the experiential dimension of religion, we turn to perspectives that take religious experience more seriously, what Lindbeck (1984) calls the ''experiential-expressive'' and ''cultural-linguistic'' views. While the former is an advance over the dominant views, it too has liabilities. We advocate the cultural-linguistic theory as die most sophisticated way of seeing religion. As a preliminary test of this view, we examine the relationship between ''ecstatic'' religious experience and ''conventional'' religiosity, predicting that the most contentional worshipers will have ecstatic experiences most frequently. Logistic regression analysis of General Social Survey data supports this prediction.
Full-text available
Article
The current study validated the three-factor, eight-facet model of Hood's Mysticism Scale and explored mean differences in mysticism with 330 indigenous Chinese Christian and 323 non-Christian participants. Confirmatory factor analysis demonstrated good fit for the overall Chinese sample and established measurement invariance of the instrument across the two groups. Both groups scored above the midpoint on the total Mysticism Scale, while Christians scored significantly higher in the mystical interpretation factor than did non-Christians. Controlling for demographic variables, multiple regression procedures revealed that a high intrinsic religious orientation mediated the association of Christian religious affiliation with mysticism. These results yielded patterns consistent with those found in the West, and suggested that the Mysticism Scale was a valid quantitative measure for exploring spirituality issues in Chinese society.
Full-text available
Article
Although psilocybin has been used for centuries for religious purposes, little is known scientifically about its acute and persisting effects. This double-blind study evaluated the acute and longer-term psychological effects of a high dose of psilocybin relative to a comparison compound administered under comfortable, supportive conditions. The participants were hallucinogen-naïve adults reporting regular participation in religious or spiritual activities. Two or three sessions were conducted at 2-month intervals. Thirty volunteers received orally administered psilocybin (30 mg/70 kg) and methylphenidate hydrochloride (40 mg/70 kg) in counterbalanced order. To obscure the study design, six additional volunteers received methylphenidate in the first two sessions and unblinded psilocybin in a third session. The 8-h sessions were conducted individually. Volunteers were encouraged to close their eyes and direct their attention inward. Study monitors rated volunteers' behavior during sessions. Volunteers completed questionnaires assessing drug effects and mystical experience immediately after and 2 months after sessions. Community observers rated changes in the volunteer's attitudes and behavior. Psilocybin produced a range of acute perceptual changes, subjective experiences, and labile moods including anxiety. Psilocybin also increased measures of mystical experience. At 2 months, the volunteers rated the psilocybin experience as having substantial personal meaning and spiritual significance and attributed to the experience sustained positive changes in attitudes and behavior consistent with changes rated by community observers. When administered under supportive conditions, psilocybin occasioned experiences similar to spontaneously occurring mystical experiences. The ability to occasion such experiences prospectively will allow rigorous scientific investigations of their causes and consequences.
Full-text available
Article
The decision of how many factors to retain is a critical component of exploratory factor analysis. Evidence is presented that parallel analysis is one of the most accurate factor retention methods while also being one of the most underutilized in management and organizational research. Therefore, a step-by-step guide to performing parallel analysis is described, and an example is provided using data from the Minnesota Satisfaction Questionnaire. Recommendations for making factor retention decisions are discussed.
Full-text available
Article
Factor analysis, path analysis, structural equation modeling, and related multivariate statistical methods are based on maximum likelihood or generalized least squares estimation developed for covariance structure models (CSMs). Large-sample theory provides a chi-square goodness-of-fit test for comparing a model (M) against a general alternative M based on correlated variables. It is suggested that this comparison is insufficient for M evaluation. A general null M based on modified independence among variables is proposed as an additional reference point for the statistical and scientific evaluation of CSMs. Use of the null M in the context of a procedure that sequentially evaluates the statistical necessity of various sets of parameters places statistical methods in covariance structure analysis into a more complete framework. The concepts of ideal Ms and pseudo chi-square tests are introduced, and their roles in hypothesis testing are developed. The importance of supplementing statistical evaluation with incremental fit indices associated with the comparison of hierarchical Ms is also emphasized. Normed and nonnormed fit indices are developed and illustrated. (43 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Full-text available
Article
Studied the effectiveness of having a "peak experience" in the process of psychotherapy with 34 terminal cancer patients. The peak experience, a radically altered form of consciousness involving profoundly positive feelings, was produced by administering 75–227.5 mg of dipropyltryptamine (DPT). Assessment with 2 sets of questionnaires indicated that the peak experience occurred in 15 patients (peakers). Retrospective examination of the patients' records indicated that the peakers had been more distressed than nonpeakers prior to the therapy. After having the experience, the patients showed marked relief from distress, as indicated by a number of tests, questionnaires, and interviews with the therapists. However, ratings before and after the therapy made by 2 social workers, who had not been informed about the purpose and method of the therapy, did not indicate any significant effect of the therapy, either in the peakers or nonpeakers. (28 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Full-text available
Article
Hood developed a Mysticism Scale based on the theoretical work of Stace. The scale was tested by Hood and others in a comparative perspective. Using an abridged version of Hood's Mysticism Scale, we join the debate with a study of a much larger number of Christian, Muslim, and Hindu respondents (1,920 college students) living in Tamil Nadu, India. Our empirical analysis yields a moderately reliable model of mystical experience that permits comparison between the three religious traditions. We argue for the usefulness of a comparative model of vertical mysticism that combines with the complementary common characteristics of noetic quality and ineffability. Vertical mysticism has a revelatory, ineffable character and is comparable in the experience of adherents of the Christian, Islamic, and Hindu traditions.
Full-text available
Article
Psychoactive drug use shows great diversity, but due to a disproportionate focus on problematic drug use, predominant nonproblematic drug use remains an understudied phenomenon. Historic and anecdotal evidence shows that natural sources of "psychedelic" drugs (e.g., mescaline and psilocybin) have been used in religious and spiritual settings for centuries, as well as for psychological self-enhancement purposes. Our study assessed a total of 667 psychedelic drug users, other drug users, and drug nonusers by online questionnaires. Coping, life purpose, and spirituality were measured with the Psychological Immune Competence Inventory, the Purpose in Life test, and the Intrinsic Spirituality Scale, respectively. Results indicate that the use of psychedelic drugs with a purpose to enhance self-knowledge is less associated with problems, and correlates positively with coping and spirituality. Albeit the meaning of "spirituality" may be ambiguous, it seems that a spiritually-inclined attitude in drug use may act as a protective factor against drug-related problems. The autognostic use of psychedelic drugs may be thus hypothesized as a "training situation" that promotes self-enhancement by rehearsing personal coping strategies and by gaining self-knowledge. However, to assess the actual efficiency and the speculated long-term benefits of these deliberately provoked exceptional experiences, further qualitative investigations are needed.
Full-text available
Article
A large body of evidence, including longitudinal analyses of personality change, suggests that core personality traits are predominantly stable after age 30. To our knowledge, no study has demonstrated changes in personality in healthy adults after an experimentally manipulated discrete event. Intriguingly, double-blind controlled studies have shown that the classic hallucinogen psilocybin occasions personally and spiritually significant mystical experiences that predict long-term changes in behaviors, attitudes and values. In the present report we assessed the effect of psilocybin on changes in the five broad domains of personality - Neuroticism, Extroversion, Openness, Agreeableness, and Conscientiousness. Consistent with participant claims of hallucinogen-occasioned increases in aesthetic appreciation, imagination, and creativity, we found significant increases in Openness following a high-dose psilocybin session. In participants who had mystical experiences during their psilocybin session, Openness remained significantly higher than baseline more than 1 year after the session. The findings suggest a specific role for psilocybin and mystical-type experiences in adult personality change.
Full-text available
Article
This dose-effect study extends previous observations showing that psilocybin can occasion mystical-type experiences having persisting positive effects on attitudes, mood, and behavior. This double-blind study evaluated psilocybin (0, 5, 10, 20, 30 mg/70 kg, p.o.) administered under supportive conditions. Participants were 18 adults (17 hallucinogen-naïve). Five 8-h sessions were conducted individually for each participant at 1-month intervals. Participants were randomized to receive the four active doses in either ascending or descending order (nine participants each). Placebo was scheduled quasi-randomly. During sessions, volunteers used eyeshades and were instructed to direct their attention inward. Volunteers completed questionnaires assessing effects immediately after and 1 month after each session, and at 14 months follow-up. Psilocybin produced acute perceptual and subjective effects including, at 20 and/or 30 mg/70 kg, extreme anxiety/fear (39% of volunteers) and/or mystical-type experience (72% of volunteers). One month after sessions at the two highest doses, volunteers rated the psilocybin experience as having substantial personal and spiritual significance, and attributed to the experience sustained positive changes in attitudes, mood, and behavior, with the ascending dose sequence showing greater positive effects. At 14 months, ratings were undiminished and were consistent with changes rated by community observers. Both the acute and persisting effects of psilocybin were generally a monotonically increasing function of dose, with the lowest dose showing significant effects. Under supportive conditions, 20 and 30 mg/70 kg psilocybin occasioned mystical-type experiences having persisting positive effects on attitudes, mood, and behavior. Implications for therapeutic trials are discussed.
Full-text available
Article
Background: The OAV questionnaire has been developed to integrate research on altered states of consciousness (ASC). It measures three primary and one secondary dimensions of ASC that are hypothesized to be invariant across ASC induction methods. The OAV rating scale has been in use for more than 20 years and applied internationally in a broad range of research fields, yet its factorial structure has never been tested by structural equation modeling techniques and its psychometric properties have never been examined in large samples of experimentally induced ASC. Methodology/principal findings: The present study conducted a psychometric evaluation of the OAV in a sample of psilocybin (n = 327), ketamine (n = 162), and MDMA (n = 102) induced ASC that was obtained by pooling data from 43 experimental studies. The factorial structure was examined by confirmatory factor analysis, exploratory structural equation modeling, hierarchical item clustering (ICLUST), and multiple indicators multiple causes (MIMIC) modeling. The originally proposed model did not fit the data well even if zero-constraints on non-target factor loadings and residual correlations were relaxed. Furthermore, ICLUST suggested that the "oceanic boundlessness" and "visionary restructuralization" factors could be combined on a high level of the construct hierarchy. However, because these factors were multidimensional, we extracted and examined 11 new lower order factors. MIMIC modeling indicated that these factors were highly measurement invariant across drugs, settings, questionnaire versions, and sexes. The new factors were also demonstrated to have improved homogeneities, satisfactory reliabilities, discriminant and convergent validities, and to differentiate well among the three drug groups. Conclusions/significance: The original scales of the OAV were shown to be multidimensional constructs. Eleven new lower order scales were constructed and demonstrated to have desirable psychometric properties. The new lower order scales are most likely better suited to assess drug induced ASC.
Article
Meditation is approached as a technique for the activation of religious experience. Various theories used in psychology to explain the cognitive changes brought about by meditation are briefly reviewed. Of these, the role-theory of Sundén fits best the structure and function of various meditation methods in religious history. A small scale laboratory experiment is reported, designed for the purpose of testing the predictive validity of role-theory. The results make it possible to specify the theory's contribution and limitation.
Article
Caird's (1988) factor-analytic study of Hood's (1975) M-scale was replicated using adult subjects (N = 87) rather than college students. Subjects included contemplative mystics, psychotics with religious preoccupations, and other adults. As in Caird's (1988) findings, our study found two factors similar to Hood's two-component solution, reflecting Unitary and Interpretive categories of mystical experience. A three-factor solution splits the Interpretive category into Noetic/Ineffability and Religious types of interpretations. The factors in both solutions are intercorrelated. This study provides additional evidence for the stability of factorial structures across diverse samples and limited evidence for validity.
Article
The effect of anticipatory set stress and setting stress on the elicitation of reported mystical experience was investigated in a natural, field context of a planned nature experience. Those persons anticipating low stress in stressful activities and settings scored higher on a measure of reported mystical experience than persons anticipating high stress in stressful activities and settings. Further analysis of a low stress activity not anticipated as stressful affirmed that anticipating low stress for a stressful activity, and not simply setting stress per se, most adequately accounts for the report of mystical experience. The relevance of these data for the positive function of set and setting stress incongruity in making one aware of both personal limits and the possibility of transcendence is briefly discussed.
Article
A measure of reported mystical experience is presented. This "Mysticism Scale, Research Form D (M scale)," has 32 items, four for each of 8 categories of mysticism initially conceptualized by Stace (1960). Items on this scale are both positively and negatively expressed to avoid problems of response set. A factor analysis of the M Scale indicated two major factors, a general mystical experience factor (20 items) and a religious interpretation factor (12 items). Preliminary evidence indicates that those high on the M Scale have more intrinsic religious motivation as defined by Hoge's (1972) scale, are more open to experience as defined by Taft's (1970) ego permissiveness scale, have more intense religious experience as defined by Hood's (1970) scale, and have moderately higher scores on the L, Hs, and Hy scales of the MMPI.
Article
Responses of 115 subjects to Hood's M-scale were subjected to principal axis factor analysis, for the purpose of verifying the factorial structure reported by Hood (1975). A two-factor solution, closely similar to Hood's two-component solution, yields factors interpretable as the Unitary and Interpretative categories of mystical experience. A three-factor solution splits the Interpretative category into Noetic and Religious types of interpretation. In both solutions, the factors are highly intercorrelated.
Article
The present study attempts to measure how individuals define the terms religiousness and spirituality, to measure how individuals define their own religiousness and spirituality, and to examine whether these definitions are associated with different demographic, religio/spiritual, and psychosocial variables. The complete sample of 346 individuals was composed of 11 groups of participants drawn from a wide range of religious backgrounds. Analyses were conducted to compare participants' self-rated religiousness and spirituality, to correlate self-rated religiousness and spirituality with the predictor variables, and to use the predictor variables to distinguish between participants who described themselves as "spiritual and religious" from those who identified themselves as "spiritual but not religious." A content analysis of participants' definitions of religiousness and spirituality was also performed. The results suggest several points of convergence and divergence between the constructs religiousness and spirituality. The theoretical, empirical, and practical implications of these results for the scientific study of religion are discussed.
Article
In this research, 73 participants were categorized according to religious orientation (intrinsic, extrinsic, or indiscriminately pro) and were subjected to an isolation tank experience under one of two set conditions (religious or nonreligious). The experience was assessed by means of a modified mysticism scale with two factors: a minimal phenomenological experience factor (I) and a religious interpretation factor (II). As predicted, religious types did not differ on the report of minimal phenomenological properties of mysticism (factor I) as a function of set conditions. However, as predicted, indiscriminately pro participants had higher factor II scores (religious interpretation) under the religious set condition, while factor II scores were unaffected by set conditions for extrinsic and intrinsic types. Also, as anticipated, intrinsic types had higher factor II scores, while extrinsic had lower factor II scores regardless of set conditions.
Article
In the study of mysticism the debate has centered on whether a universal experiential core exists regardless of religious interpretation. The current investigation combines Jamesian empiricist and social constructivist perspectives to argue that stable experiential facets load variously on factors to construct local interpretations. Local interpretations reflect a family resemblance—a mystical common core experienced across cultures. Results of confirmatory factor analyses, based on data from 240 Tibetan Buddhist adults, suggest statistical model fit and superiority for the three-factor model compared to the unidimensional model. Pure experience can be distinguished explicitly from its context-specific hermeneutical construal.
Article
This study explores the phenomenological structure of mystical experience among 139 Chinese Pure Land and Chan Buddhist monks and nuns. Semi‐structured interviews, thematic coding, and statistical analyses demonstrated that Stace's common facets of mysticism as measured by Hood's Mysticism Scale (M Scale) successfully described Buddhist experience as modified by Buddhist doctrines. Confirmatory factor analysis (CFA) revealed that these facets could be formed into Stace's three‐factor structure. A mystical introvertive unity hypothesized to be separate from an extrovertive unity instead converged in the Chinese Buddhist context. These results lend strong support to the thesis that the phenomenology of mystical experience reveals a common experiential core that can be discerned across religious and spiritual traditions. These data also demonstrated that this common core can and should be explored using mixed methods.
Article
In a mostly Christian American sample (N = 1,379), confirmatory factor analysis of Hood’s (1975) Mysticism Scale verified the existence of Stace’s (1960) introvertive and extrovertive dimensions of mystical phenomenology along with a separate interpretation factor. A second study confirmed the presence of these three factors in not only another group of Americans (N = 188), but also in a sample of Iranian Muslims (N = 185). Relationships of the introvertive and extrovertive factors with the interpretation factor were essentially identical across these two cultures, but the Americans displayed a stronger association between the two phenomenology factors. In both samples, the interpretation factor correlated positively with an intrinsic and negatively with an extrinsic religious orientation, and the introvertive factor predicted psychological dysfunction. Associations of the interpretation factor with relative mental health appeared only in the Iranians. These data offered general support for Stace’s phenomenology of mysticism, although the ineffability he linked with interpretation proved to be as much or even more a feature of the introvertive experience, as hypothesized by Hood.