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Psychedelic drugs are creating ripples in psychiatry as evidence accumulates of their therapeutic potential. An important question remains unresolved however: how are psychedelics effective? We propose that a sense of connectedness is key, provide some preliminary evidence to support this, and suggest a roadmap for testing it further.
Psychedelics and connectedness
R. L. Carhart-Harris
&D. Erritzoe
&E. Haijen
&M. Kaelen
&R. Watts
Received: 18 June 2017 /Accepted: 19 July 2017
#Springer-Verlag GmbH Germany 2017
Abstract Psychedelic drugs are creating ripples in psychiatry
as evidence accumulates of their therapeutic potential. An
important question remains unresolved however: how are psy-
chedelics effective? We propose that a sense of connectedness
is key, provide some preliminary evidence to support this, and
suggest a roadmap for testing it further.
We are in the midst of a cultural zeitgeist with regard to psy-
chedelic drugs such as psilocybin, LSD and DMT (ayahuasca)
(Carhart-Harris and Goodwin 2017). April 2017 featured the
largest ever conference on the topic, Psychedelic Science,in
Oakland, California, attended by 3000 people from over 40
different countries. Among the 175+ speakers were Tom Insel
(former director of the National Institute for Mental Health)
and Paul Summergrad (past president of the American
Psychiatric Association), speaking enthusiastically and en-
couragingly about the field, symbolic in some sense of its
present main-streaming(Carhart-Harris and Goodwin
The theme of connectedness was pervasive at Psychedelic
Science, featuring consistently among speakerspresentations.
To our knowledge, the concept was first given clear emphasis
in psychedelic therapy by Watts et al. 2017, in a qualitative
research paper linked to our recent psilocybin for treatment-
resistant depression (TRD) clinical trial (Carhart-Harris et al.
2016)see also (Belser et al. 2017). In 6-month follow-up
interviews, participants were asked: Did this treatment work
for you, and if so how?and responses were analysed for
consistent themes (Watts et al. 2017). Of the 17 patients who
endorsed the treatmentseffectiveness,all made reference to
one particular mediating factor: a renewed sense of connection
or connectedness. This factor was found to have three distin-
guishable aspects: connection to (1) self,(2)others and (3) the
world in general (Watts et al. 2017). For many, the sense of
connectedness featured acutely, during the treatment session
itself, but just as commonly, it endured for several weeks to
months afterwards, as can be seen here from a participant who
remained in remission for 3-months post-treatment:
This connection, its just a lovely feelingthis sense of
connectedness, we are all interconnected.(male, aged
Asenseofdisconnection is a feature of many major psy-
chiatric disorders, particularly depression (Karp 2017), and a
sense of connection or connectedness is considered a key me-
diator of psychological well-being (Cervinka et al. 2012;Lee
et al. 2008), as well as a factor underlying recovery of mental
health (Leamy et al. 2011). One of the most curious aspects of
the growing literature on the therapeutic potential of psyche-
delics is the seeming general nature of their therapeutic appli-
cability (Carhart-Harris and Goodwin 2017), i.e. they have
shown promise not just for the treatment of depression but
for addictions, anxiety and obsessive-compulsive disorder
(Carhart-Harris and Goodwin 2017). This raises the question
of whether psychedelic therapy targets a core factor underly-
ing mental health. We believe that it does, and that
connectedness is the key (Watts et al. 2017).
Like any construct in psychology, connectedness requires
validation work. Validated measures of social connectedness
(Lee and Robbins 1995)andconnectedness to nature
(Mayer and Frantz 2004) already exist. We recently showed
*R. Watts
Psychedelic Research Group, Centre for Psychiatry, Department of
Medicine, Imperial College London, W12 0NN, London, UK
DOI 10.1007/s00213-017-4701-y
that feelings of connectedness to nature are increased post-
psilocybin (Lyons et al. 2017, under review)and see also
(Forstmann and Sagioglou 2017)and correlate with the ex-
tent of past psychedelic drug-use and intensity of ego-disso-
lutionexperienced under a psychedelic (Nour et al. 2017).
There already exist ample behavioural indices of connection
to othersand worldin various guises, and new measures
could be easily devised and developed.
We are presently collecting longitudinal data on social con-
nectedness in individuals who plan a psychedelic experience
and provide web-based survey data on the process. Figure 1
displays some relevant preliminary data from this project,
showing increased social connectedness and psychological
well-being 2 weeks after an experience, plus the significant
positive relationship between them. These data were collected
from a sample of over 200 people. Future work, featuring
mediation modelling could determine whether aspects of the
acute psychedelic experience such as ego-dissolution(Nour
et al. 2016), mystical experience(Barrett et al. 2015)and
awe(Piff et al. 2015) mediate the long-term positive effects
of psychedelics and whether increased connectedness is a
principal component of post-psychedelic therapeutic
changeas we suspect (Watts et al. 2017).
As noted above, connectedness,asitwasdescribedbypa-
tients in our TRD trial, encompassed not just connection to
others (i.e. social connectedness) and the world in general
(e.g. connectedness to nature) but also connection to the self
(Watts et al. 2017). Post-treatment, participants referred to feel-
ing reconnected to past values, pleasures and hobbies as well as
feeling more integrated, embodied and at peace with them-
selves and their often troubled backgrounds. It is a working
hypothesis of ours that connection-to-self is a bedrock from
which connection to others and the world can follow most
naturally. Another hypothesis is that positive therapeutic out-
comes could be jeopardised if the primary connection-to-self
stage is leap-frogged, e.g. due to incomplete psychological
integration (Richards 2015).
Yesterday I was clever, so I wanted to change the world.
Today I am wise, so I am changing myself.(Jalaluddin
Arelevantscaleformeasuringconnection-to-self might be
the quiet ego scale(Wayment et al. 2015). However, we feel
there is much scope for a new connectedness scale that can
incorporate the three sub-factors identified in our recent qual-
itative analysis (Watts et al. 2017), namely connection-to-self,
others and world in general. The scales mentioned above
could serve as tools to test convergent validity; measures of
well-being and psychiatric symptoms could serve as tests of
clinical usefulness and comparator drugs could be incorporat-
ed to test the hypothesis that there is a selective relationship
between psychedelics and connectedness that does not exist
for other psychoactive drugs such as alcohol (chronic and
excessive use especially), stimulants and conventional psychi-
atric medications such as the selective serotonin reuptake in-
hibitors (SSRIs). It is notable in this regard that many patients
in our TRD trial felt that the process and effect of being pre-
scribed conventional treatments merely reinforced their sense
Fig. 1 Measures collected before and 2 weeks after a planned
psychedelic drug experience, as part of a longitudinal web-based survey
project that will be reported on in detail in future publications (https:// Well-being was measured with the
Warwick Edinburgh Well-being Scale (Tennant et al. 2007) and scores
range from 14 to 70; social connectedness was measured with the Social
Connectedness Scale (Lee and Robbins 1995) and scores range from 8 to
48. Significant increases in both measures were seen post-psychedelic
(n=204,**p<0.01,pairedttest), and there was a significant positive
relationship between their respective change scores (r=0.387,p<0.01)
of disconnection (Watts et al. 2017). Moreover, stimulant use
has been associated with hubris and individualism and alcohol
use with a lack of concern for nature and the environment
(Nour et al. 2017).
We ar e mindf ul o f the scien ti fical ly d elica te a ssoci at io n
between psychedelics and mystical experience.Despite
previously expressed concerns regarding this construct
(Carhart-Harris and Goodwin 2017), psychedelic-induced
mystical experiences have been found to predict long-
term increases in psychological well-being (Griffiths
et al. 2006) as well as clinical improvements after psyche-
delic therapy (Carhart-Harris and Goodwin 2017). Given
the apparent positive mediational value of such experiences, it
seems pertinent to better understand where their value lies,
and again, we suspect that connectedness may be the key.
Writing in 1960, philosopher Walter Stace referred to the
unitive experience(a sense of onenessor unity)asthe core
hallmark of the mystical experience. Items pertaining to a sense
of onenessform a major part of leading measures of mystical
experience, including the recently validated mystical experi-
ence questionnaire (MEQ)(Barrett et al. 2015). The unitive
experience is closely related to the construct of connectedness.
We re centl y fo un d that sc or esofpsychedelic-inducedunitive
experience correlate highly with scores of ego-dissolution
(Nour et al. 2016). Conceptually, one can consider the ego as
a counter-force to connectedness. Consider for example, an
item from our recently developed ego-inflationmeasure,
scores on which correlated positively with cocaine-use and
negatively with psychedelic-use (Nour et al. 2016): Ifeltmore
important or special than others.Notehowthiscontrastswith
items from the following: (1) our ego-dissolution inventoryor
EDI (Nour et al. 2016): Ifeltfarlessabsorbedbymyown
issues and concerns;(
2) the MEQ: Freedom from the limita-
tions of your personal self and feeling a unity or bond with what
was felt to be greater than your personal self^;(3)theconnect-
edness to nature scale (Mayer and Frantz 2004): Ioftenfeela
sense of oneness with the natural world around meand a
small selfmeasure used in research on awe:Ifeelthepres-
ence of something greater than myself(Piff et al. 2015).
Part of our focus within the Psychedelic Research Group at
Imperial College London has been to better understand the
brain mechanisms of psychedelics, including their putative
therapeutic actions, and while brain imaging adds a perceived
sophistication to psychedelic research, psychological mecha-
nisms are at least as importantoffering a level of explanation
that is closer to the lived-experience, broadly accessible and
also potentially most useful, e.g. in terms of cost-effectively
predicting treatment effectiveness (Carrillo et al. 2017).
Human brain imagings special appeal lies in its ability to
open the black box’—revealing insights about major un-
knownsbut imaging findings can also be misused, e.g. in
terms of excessive reverse inference (Poldrack 2006)and
neuro-realism(Racine et al. 2010). Even so, we recognise
that the healthy demystification process that is presently taking
place in psychedelic research relies in no small part on the
identification of biological substrates of high-level subjective
experiences, and we have no doubt that both an acute and
enduring sense of connectedness have identifiable biological
Our work on the neural correlates of ego-dissolutionmay
be considered part of a progressive initiative to demystify the
psychedelic experience (Tagliazucchi et al. 2016;Nouretal.
2016). Like ego-dissolution and entropy(Carhart-Harris
et al. 2014), connectedness is particularly appealing as a con-
struct because it carries meaning in both mechanistic and sub-
jective sense. Our finding of increased global functional con-
nectivity in the psychedelic brainand its relationship to ego-
dissolution (Tagliazucchi et al. 2016) may be considered a
candidate neural correlate of the unitive experiencei.e.
connectedness in its acute form. How this relates to longer-
term feelings of connectedness,however,isperhapsamore
challenging question. Does the unitive experience leave a last-
ing memory trace, analogous to the overview effectexperi-
enced by some astronauts (White 1987)characterised by a
sense of aweand perceived smallness in the presence of
vastness (Piff et al. 2015) or does the psychedelic experiences
cause lasting anatomical and/or functional brain changes?
These possibilities need not be mutually exclusive, and only
properly supported empirical research can advance and even-
tually resolve these matters. We hope that mainstream funding
bodies be broadminded and brave enough to see the possibil-
ities here, as the potential rewards for science and society may
be great.
Finally, it seems remarkable that we can discuss high-level
constructs such as connectednesswhile knowing psyche-
delicsaction at the molecular level. For example, we know
that psychedelics initiate their signature subjective effects via
serotonin 2A-receptor agonism (Carhart-Harris and Nutt
2017). Since psychedelics hijackan existing system, it is
natural to ask what evolutionary role that system has played
throughout our speciesdevelopmentand whether under-
standing this may shed light on our understanding of the func-
tioning of brain serotonin more generally. Relevant questions
have recently been explored (Carhart-Harris and Nutt 2017).
In brief, we have proposed that brain serotonin 2A receptor
signalling mediates a state of rapid plasticity that is conducive
to major change (e.g. in outlook and/or behaviour)when
such change feels necessary (e.g. to aid mental or physical
survival). Such a function may be related to humansunique
capacity for adaptability.
Moving forward, we intend to develop an operational defi-
nition of connectedness that incorporates not just connectedness
in the subjective sense but also its biological basis and various
behavioural manifestations. Crucially, such a definition should
be meaningful and useful not just in the context of psyche-
delicsbut universally.
Acknowledgements RLC-H is supported by the Alex Mosley
Charitable Trust. RW is supported by Compass Pathways.
Author contributions RW conceived of the notion and importance of
connectedness through her follow-up to our recent psilocybin for TRD
trial. RCH wrote this paper with feedback from RW, DE and MK. MK
and EH provided the data for Fig. 1, and EH made the figure. DE pro-
vided intellectual input regarding the central construct plus editorial ad-
vice. All authors read and approved the final manuscript.
Compliance with ethical standards
Conflicts of interest The authors declare that they have no conflicts of
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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.
Psychedelic substances have played important roles in diverse cultures, and ingesting various plant preparations to evoke altered states of consciousness has been described throughout recorded history. Accounts of the subjective effects of psychedelics typically focus on spiritual and mystical-type experiences, including feelings of unity, sacredness, and transcendence. Over the past two decades, there has been increasing interest in psychedelics as treatments for various medical disorders, including chronic pain. Although concerns about adverse medical and psychological effects contributed to their controlled status, contemporary knowledge of psychedelics suggests that risks are relatively rare when patients are carefully screened, prepared, and supervised. Clinical trial results have provided support for the effectiveness of psychedelics in different psychiatric conditions. However, there are only a small number of generally uncontrolled studies of psychedelics in patients with chronic pain (e.g., cancer pain, phantom limb pain, migraine, and cluster headache). Challenges in evaluating psychedelics as treatments for chronic pain include identifying neurobiologic and psychosocial mechanisms of action and determining which pain conditions to investigate. Truly informative proof-of-concept and confirmatory randomized clinical trials will require careful selection of control groups, efforts to minimize bias from unblinding, and attention to the roles of patient mental set and treatment setting. Perspective: There is considerable promise for the use of psychedelic therapy for pain, but evidence-based recommendations for the design of future studies are needed to ensure that the results of this research are truly informative.
The current article presents a mixed qualitative-quantitative observational study of the effect of ayahuasca ritual on subjective experiences and personality traits on participants of a center specialized in the treatment of substance use disorder in Uruguay. When comparing the psychological traits of ayahuasca participants to a control group, quantitative results using the Zuckerman-Kuhlman-Aluja Personality Questionnaire showed statistically significant higher scores in Impulsive Sensation Seeking, Boredom Susceptibility, and Social Warmth scales. Qualitative analysis of ayahuasca experiences resulted in five main categories: emotional experiences (including social emotions such as love and empathy), corporal experiences, spiritual/transcendental experiences, personal experiences, and visions. Last, qualitative descriptions provide support for the importance of social interactions in the phenomenological manifestations of the psychedelic experience. Both quantitative and qualitative results suggest that the combination of social interactions and the pharmacological action of ayahuasca could facilitate the manifestation of social emotions during the ritual, and may contribute to the long-term increase of empathic and social aspects of personality.
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Previous attempts to identify a unified theory of brain serotonin function have largely failed to achieve consensus. In this present synthesis, we integrate previous perspectives with new and older data to create a novel bipartite model centred on the view that serotonin neurotransmission enhances two distinct adaptive responses to adversity, mediated in large part by its two most prevalent and researched brain receptors: the 5-HT1A and 5-HT2A receptors. We propose that passive coping (i.e. tolerating a source of stress) is mediated by postsynaptic 5-HT1AR signalling and characterised by stress moderation. Conversely, we argue that active coping (i.e. actively addressing a source of stress) is mediated by 5-HT2AR signalling and characterised by enhanced plasticity (defined as capacity for change). We propose that 5-HT1AR-mediated stress moderation may be the brain's default response to adversity but that an improved ability to change one's situation and/or relationship to it via 5-HT2AR-mediated plasticity may also be important - and increasingly so as the level of adversity reaches a critical point. We propose that the 5HT1AR pathway is enhanced by conventional 5-HT reuptake blocking antidepressants such as the selective serotonin reuptake inhibitors (SSRIs), whereas the 5-HT2AR pathway is enhanced by 5-HT2AR-agonist psychedelics. This bipartite model purports to explain how different drugs (SSRIs and psychedelics) that modulate the serotonergic system in different ways, can achieve complementary adaptive and potentially therapeutic outcomes.
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The psychological mechanisms of action involved in psilocybin-assisted psychotherapy are not yet well understood. Despite a resurgence of quantitative research regarding psilocybin, the current study is the first qualitative study of participant experiences in psilocybin-assisted psychotherapy. Semistructured interviews were carried out with 13 adult participants aged 22 to 69 years (M = 50 years) with clinically elevated anxiety associated with a cancer diagnosis. Participants received a moderate dose of psilocybin and adjunctive psychotherapy with an emphasis on the process of meaning-making. Verbatim transcribed interviews were analyzed by a five-member research team using interpretative phenomenological analysis. General themes found in all or nearly all transcripts included relational embeddedness, emotional range, the role of music as conveyor of experience, meaningful visual phenomena, wisdom lessons, revised life priorities, and a desire to repeat the psilocybin experience. Typical themes found in the majority of transcripts included the following: exalted feelings of joy, bliss, and love; embodiment; ineffability; alterations to identity; a movement from feelings of separateness to interconnectedness; experiences of transient psychological distress; the appearance of loved ones as guiding spirits; and sharing the experience with loved ones posttreatment. Variant themes found in a minority of participant transcripts include lasting changes to sense of identity, synesthesia experiences, catharsis of powerful emotion, improved relationships after treatment, surrender or “letting go,” forgiveness, and a continued struggle to integrate experience. The findings support the conclusion that psilocybin-assisted psychotherapy may provide an effective treatment for psychological distress in cancer patients. Implications for theory and treatment are discussed.
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Plant-based psychedelics such as psilocybin have an ancient history of medicinal use. After the first English-language report on LSD in 1950, psychedelics enjoyed a short-lived relationship with psychology and psychiatry. Used most notably as aides to psychotherapy for the treatment of mood disorders and alcohol dependence, drugs such as LSD showed initial therapeutic promise before prohibitive legislature in the mid-1960s effectively ended all major psychedelic research programmes. Since the early 1990s, there has been a steady revival of human psychedelic research: last year saw reports on the first modern brain imaging study with LSD and 3 separate clinical trials of psilocybin for depressive symptoms. In this Circumspective piece, Robin Carhart-Harris and Guy Goodwin share their opinions on the promises and pitfalls of renewed psychedelic research, with a focus on the development of psilocybin as a treatment for depression.Neuropsychopharmacology accepted article preview online, 26 April 2017. doi:10.1038/npp.2017.84.
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Aims: The experience of a compromised sense of “self”, termed ego-dissolution, is a key feature of the psychedelic experience. This study aimed to validate the Ego-Dissolution Inventory (EDI), a new 8-item self-report scale designed to measure ego-dissolution. Additionally, we aimed to investigate the specificity of the relationship between psychedelics and ego-dissolution. Method: Sixteen items relating to altered ego-consciousness were included in an internet questionnaire; eight relating to the experience of ego-dissolution (comprising the EDI), and eight relating to the antithetical experience of increased self-assuredness, termed ego-inflation. Items were rated using a visual analog scale. Participants answered the questionnaire for experiences with classical psychedelic drugs, cocaine and/or alcohol. They also answered the seven questions from the Mystical Experiences Questionnaire (MEQ) relating to the experience of unity with one’s surroundings. Results: Six hundred and ninety-one participants completed the questionnaire, providing data for 1828 drug experiences (1043 psychedelics, 377 cocaine, 408 alcohol). Exploratory factor analysis demonstrated that the eight EDI items loaded exclusively onto a single common factor, which was orthogonal to a second factor comprised of the items relating to ego-inflation (rho = −0.110), demonstrating discriminant validity. The EDI correlated strongly with the MEQ-derived measure of unitive experience (rho = 0.735), demonstrating convergent validity. EDI internal consistency was excellent (Cronbach’s alpha 0.93). Three analyses confirmed the specificity of ego-dissolution for experiences occasioned by psychedelic drugs. Firstly, EDI score correlated with drug-dose for psychedelic drugs (rho = 0.371), but not for cocaine (rho = 0.115) or alcohol (rho = −0.055). Secondly, the linear regression line relating the subjective intensity of the experience to ego-dissolution was significantly steeper for psychedelics (unstandardized regression coefficient = 0.701) compared with cocaine (0.135) or alcohol (0.144). Ego-inflation, by contrast, was specifically associated with cocaine experiences. Finally, a binary Support Vector Machine classifier identified experiences occasioned by psychedelic drugs vs. cocaine or alcohol with over 85% accuracy using ratings of ego-dissolution and ego-inflation alone. Conclusion: Our results demonstrate the psychometric structure, internal consistency and construct validity of the EDI. Moreover, we demonstrate the close relationship between ego-dissolution and the psychedelic experience. The EDI will facilitate the study of the neuronal correlates of ego-dissolution, which is relevant for psychedelic-assisted psychotherapy and our understanding of psychosis.
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Background: Psilocybin is a serotonin receptor agonist that occurs naturally in some mushroom species. Recent studies have assessed the therapeutic potential of psilocybin for various conditions, including end-of-life anxiety, obsessive-compulsive disorder, and smoking and alcohol dependence, with promising preliminary results. Here, we aimed to investigate the feasibility, safety, and efficacy of psilocybin in patients with unipolar treatment-resistant depression. Methods: In this open-label feasibility trial, 12 patients (six men, six women) with moderate-to-severe, unipolar, treatment-resistant major depression received two oral doses of psilocybin (10 mg and 25 mg, 7 days apart) in a supportive setting. There was no control group. Psychological support was provided before, during, and after each session. The primary outcome measure for feasibility was patient-reported intensity of psilocybin's effects. Patients were monitored for adverse reactions during the dosing sessions and subsequent clinic and remote follow-up. Depressive symptoms were assessed with standard assessments from 1 week to 3 months after treatment, with the 16-item Quick Inventory of Depressive Symptoms (QIDS) serving as the primary efficacy outcome. This trial is registered with ISRCTN, number ISRCTN14426797. Findings: Psilocybin's acute psychedelic effects typically became detectable 30-60 min after dosing, peaked 2-3 h after dosing, and subsided to negligible levels at least 6 h after dosing. Mean self-rated intensity (on a 0-1 scale) was 0·51 (SD 0·36) for the low-dose session and 0·75 (SD 0·27) for the high-dose session. Psilocybin was well tolerated by all of the patients, and no serious or unexpected adverse events occurred. The adverse reactions we noted were transient anxiety during drug onset (all patients), transient confusion or thought disorder (nine patients), mild and transient nausea (four patients), and transient headache (four patients). Relative to baseline, depressive symptoms were markedly reduced 1 week (mean QIDS difference -11·8, 95% CI -9·15 to -14·35, p=0·002, Hedges' g=3·1) and 3 months (-9·2, 95% CI -5·69 to -12·71, p=0·003, Hedges' g=2) after high-dose treatment. Marked and sustained improvements in anxiety and anhedonia were also noted. Interpretation: This study provides preliminary support for the safety and efficacy of psilocybin for treatment-resistant depression and motivates further trials, with more rigorous designs, to better examine the therapeutic potential of this approach. Funding: Medical Research Council.
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Lysergic acid diethylamide (LSD) is a non-selective serotonin-receptor agonist that was first synthesized in 1938 and identified as (potently) psychoactive in 1943. Psychedelics have been used by indigenous cultures for millennia [1]; however, because of LSD's unique potency and the timing of its discovery (coinciding with a period of major discovery in psychopharmacology), it is generally regarded as the quintessential contemporary psychedelic [2]. LSD has profound modulatory effects on consciousness and was used extensively in psychological research and psychiatric practice in the 1950s and 1960s [3]. In spite of this, however, there have been no modern human imaging studies of its acute effects on the brain. Here we studied the effects of LSD on intrinsic functional connectivity within the human brain using fMRI. High-level association cortices (partially overlapping with the default-mode, salience, and frontoparietal attention networks) and the thalamus showed increased global connectivity under the drug. The cortical areas showing increased global connectivity overlapped significantly with a map of serotonin 2A (5-HT2A) receptor densities (the key site of action of psychedelic drugs [4]). LSD also increased global integration by inflating the level of communication between normally distinct brain networks. The increase in global connectivity observed under LSD correlated with subjective reports of "ego dissolution." The present results provide the first evidence that LSD selectively expands global connectivity in the brain, compromising the brain's modular and "rich-club" organization and, simultaneously, the perceptual boundaries between the self and the environment.
In a large-scale (N = 1487) general population online study, we investigated the relationship between past experience with classic psychedelic substances (e.g. LSD, psilocybin, mescaline), nature relatedness, and ecological behavior (e.g. saving water, recycling). Using structural equation modeling we found that experience with classic psychedelics uniquely predicted self-reported engagement in pro-environmental behaviors, and that this relationship was statistically explained by people’s degree of self-identification with nature. Our model controlled for experiences with other classes of psychoactive substances (cannabis, dissociatives, empathogens, popular legal drugs) as well as common personality traits that usually predict drug consumption and/or nature relatedness (openness to experience, conscientiousness, conservatism). Although correlational in nature, results suggest that lifetime experience with psychedelics in particular may indeed contribute to people’s pro-environmental behavior by changing their self-construal in terms of an incorporation of the natural world, regardless of core personality traits or general propensity to consume mind-altering substances. Thereby, the present research adds to the contemporary literature on the beneficial effects of psychedelic substance use on mental wellbeing, hinting at a novel area for future research investigating their potentially positive effects on a societal level. Limitations of the present research and future directions are discussed.
The psychedelic experience (including psychedelic-induced ego dissolution) can effect lasting change in a person's attitudes and beliefs. Here, we aimed to investigate the association between naturalistic psychedelic use and personality, political perspectives, and nature relatedness using an anonymous internet survey. Participants (N = 893) provided information about their naturalistic psychedelic, cocaine, and alcohol use, and answered questions relating to personality traits of openness and conscientiousness (Ten-Item Personality Inventory), nature relatedness (Nature-Relatedness Scale), and political attitudes (one-item liberalism-conservatism measure and five-item libertarian-authoritarian measure). Participants also rated the degree of ego dissolution experienced during their "most intense" recalled psychedelic experience (Ego-Dissolution Inventory). Multivariate linear regression analysis indicated that lifetime psychedelic use (but not lifetime cocaine use or weekly alcohol consumption) positively predicted liberal political views, openness and nature relatedness, and negatively predicted authoritarian political views, after accounting for potential confounding variables. Ego dissolution experienced during a participant's "most intense" psychedelic experience positively predicted liberal political views, openness and nature relatedness, and negatively predicted authoritarian political views. Further work is needed to investigate the nature of the relationship between the peak psychedelic experience and openness to new experiences, egalitarian political views, and concern for the environment.