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Rationale Microdosing psychedelics—the regular consumption of small amounts of psychedelic substances such as LSD or psilocybin—is a growing trend in popular culture. Recent studies on full-dose psychedelic psychotherapy reveal promising benefits for mental well-being, especially for depression and end-of-life anxiety. While full-dose therapies include perception-distorting properties, microdosing mayprovide complementary clinical benefits using lower-risk, non-hallucinogenic doses. Objectives This pre-registered study aimed to investigate whether microdosing psychedelics is related to differences in personality, mental health, and creativity. Methods In this observational study, respondents recruited from online forums self-reported their microdosing behaviors and completed questionnaires concerning dysfunctional attitudes, wisdom, negative emotionality, open-mindedness, and mood. Respondents also performed the Unusual Uses Task to assess their creativity. Results Current and former microdosers scored lower on measures of dysfunctional attitudes (p < 0.001, r = − 0.92) and negative emotionality (p = 0.009, r = − 0.85) and higher on wisdom (p < 0.001, r = 0.88), openmindedness(p = 0.027, r = 0.67), and creativity (p < 0.001, r = 0.15) when compared to non-microdosing controls. Conclusions These findings provide promising initial evidence that warrants controlled experimental research to directly test safety and clinical efficacy. As microdoses are easier to administer than full-doses, this new paradigm has the exciting potential to shape future psychedelic research.
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Microdosing Psychedelics: Personality, mental health, and creativity differences in
Thomas Anderson, Rotem Petranker*, Le-Anh Dinh-Williams, Daniel Rosenbaum, Cory
Weissman, Emma Hapke, Katrina Hui, & Norman Farb
Accepted to Pharmacology
*corresponding author:
Microdosing psychedelics the regular consumption of small amounts of psychedelic
substances such as LSD or psilocybin is a growing trend in popular culture. Recent studies on
full-dose psychedelic psychotherapy reveal promising benefits for mental well-being, especially
for depression and end-of-life anxiety. While full-dose therapies include perception-distorting
properties, microdosing may provide complementary clinical benefits using lower-risk, non-
hallucinogenic doses. No experimental study has evaluated psychedelic microdosing, however;
this pre-registered study is the first to investigate microdosing psychedelics and mental health.
Recruited from online forums, current and former microdosers scored lower on measures of
dysfunctional attitudes and negative emotionality and higher on wisdom, open-mindedness, and
creativity when compared to non-microdosing controls. These findings provide promising initial
evidence that warrants controlled experimental research to directly test safety and clinical
efficacy. As microdoses are easier to administer than full-doses, this new paradigm has the
exciting potential to shape future psychedelic research.
1. Introduction
Microdosing psychedelics the practice of regularly consuming very low doses of
psychedelic substances such as lysergic acid diethylamide (LSD) or psilocybin (“magic”
mushrooms) is a growing practice despite a lack of scientific research validating its effects.
One online microdosing forum (/r/microdosing subreddit, Reddit Inc, San Francisco, CA, USA)
has almost 40,000 subscribers and doubled its subscriber count in the past year (Figure 1). The
popular media has described consumption of psychedelics in doses much lower than typical
therapeutic doses (Fadiman, 2011; Leonard, 2015; Solon, 2016; Waldman, 2017) and articles and
anecdotes claim benefits including improved mood, focus, and creativity alongside decreased
symptoms of depression and anxiety. While decreased depression and anxiety are consistent with
research on full-dose psychedelics (Carhart-Harris et al., 2017; Griffiths et al., 2016),
microdosing could offer these benefits without any perceptual distortions and reduced need for
expensive clinical oversight typical of full-dose psychedelic psychotherapy. Nevertheless, both
LSD and psilocybin are controlled substances in most countries and so members of the public
enticed by purported benefits of microdosing expose themselves to the risks implied by
criminalized activity. For example, in the US, LSD and psilocybin are schedule I controlled
substances, meaning that they have no accepted therapeutic use. Such risks are exacerbated by an
absence of even minimal scientific evidence that normally surrounds clinical use, such as data on
safety, efficacy, common side-effects, contraindications, and appropriate dose and dose schedule.
Figure 1. Rise in subscribers to an online microdosing forum, As of
October 2018, the subscriber count has reached nearly 40,000 subscribers, doubling in less than
one year.
It is unlikely that normative standards for microdosing will emerge without an initial
description of current microdosing practices and associated outcomes. We therefore measured
self-reported practices and psychological function of participants in existing microdosing
communities and compared them to control participants with no microdosing experience. This
design allows for a structured description of the common practices used in microdosing from
which future clinical trials can build.
1.1 Full-dose Psychedelics
Interest in microdosing is likely predicated on research linking clinical benefits to full-
dose psychedelic use. By 1975, over one thousand studies had linked psychedelic substance use
with salutary effects on mental health and personal growth (Greenspoon & Bakalar, 1979). More
recent research suggests efficacy for a number of health conditions, including obsessive
compulsive disorder (Moreno et al., 2006), alcohol dependence (Bogenschutz et al., 2015),
tobacco dependence (Johnson et al., 2014), depression (Carhart-Harris et al., 2017; Osório et al.,
2015), and end-of-life anxiety (Griffiths et al., 2016; Ross et al., 2016).
While research on psychedelics provides evidence for the therapeutic effects of full-
doses, such experiences are often quite intense thus confer substantive participant risk. Popular
vernacular includes the term "bad trip", and, indeed, one study participant described a full-dose
experience as "the worst experience of her life" (Griffiths et al., 2011). In an online survey of the
worst “bad trips” experienced, 39% percent of participants rated their psychedelic experience
among the top five most challenging experiences of his/her lifetime (Carbonaro et al., 2016). At
the same time, Carbonaro et al. (2016) also found that despite the difficult experiences, 84% of
participants reported benefitting from the experience. Although research on LSD and psilocybin
suggest low risks for abuse or harmful effects (Amsterdam et al., 2011; Halpern and Pope, 1999;
Johnson et al., 2018), a small percentage of users are at risk of developing persisting perceptual
effects (Hallucinogen Persisting Perception Disorder; Martinotti et al., 2018) or risk being
hospitalized for acute intoxication, especially if mixed with alcohol (Hardaway et al., 2016).
While large population studies suggest that psychedelics are not usually associated with
detrimental mental health outcomes (Krebs & Johansen, 2013), microdosing may circumvent this
issue as anecdotal reports suggest numerous positive outcomes without the risks associated with
acute full-dose intoxication (Fadiman, 2011).
1.2 The Present Study
In this study we describe the psychological profile of the growing microdosing
community by making comparisons against a population of non-microdosers. We compared
groups of self-described microdosers (current and former microdosers) against controls (no
microdosing experience) across a variety of mental health and personality variables. These
include dysfunctional attitudes (de Graaf et al., 2009), wisdom (Glück et al., 2013), negative
emotionality and open-mindedness (Soto and John, 2016), and creativity (Silvia, 2011). This
study is part of a larger project that also reports on the demographics and psychiatric history of
microdosing users (Rosenbaum et al., 2018). A qualitative report examining subjective benefits
and drawbacks of microdosing is also in preparation (Anderson et al., 2018). We presently
address pre-registered hypotheses about the outcomes associated with microdosing experience on
validated scales.
2. Methods
2.1 Pre-Registered Hypotheses
Prior to data collection this study was pre-registered on the Open Science Framework
(OSF; We define "Microdosers" as those participants with experience
microdosing, whether current or former use. We pre-registered the following hypotheses:
Mental Health Vulnerability, Wisdom, and Personality
While the mechanisms driving psychedelic substances’ clinical efficacy are unclear,
several psychological constructs are likely involved. These include practical indicators of
flourishing, such as freedom from dysfunctional beliefs about oneself, other people, and the
world; wisdom; and personality traits, especially neuroticism and openness to experiences.
Psychedelic substances are purported to have profound effects on one’s understanding of
the self and world, leading to enhanced insight and personal growth (Domínguez-Clavé et al.,
2016; Dos Santos et al., 2016; Kometer et al., 2015; Strassman, 2016). As such, we hypothesized
that microdosers would have lower dysfunctional attitudes and higher wisdom than non-
microdosers. Furthermore, improved mood and reduced mental health concerns are commonly
reported outcomes of microdosing online (/r/microdosing subreddit, Reddit Inc, San Francisco,
CA, USA). For this reason, we hypothesized that microdosers would have lower negative
emotionality (depression, anxiety, and emotional volatility) than non-microdosers. Finally,
participants experiencing a single full dose of psilocybin showed a robust and sustained increase
in openness (MacLean et al., 2011); we therefore predicted that microdosers would also have
higher openness.
H1a: Microdosers will have lower dysfunctional attitude scores than non-microdosers.
H1b: Microdosers will have higher wisdom scores than non-microdosers.
H1c: Microdosers will have lower negative emotionality scores than non-microdosers.
H1d: Microdosers will have higher open-mindedness scores than non-microdosers.
The Broaden and Build theory (Fredrickson, 2004) proposes a link between positive
emotions and relaxed cognitive constraints as improved well-being may recruit personal
resources in the generation of creative ways of coping with challenges. Enhanced creativity is
one of the commonly reported outcomes of microdosing in media reports (Solon, 2016) and
online (/r/microdosing subreddit, Reddit Inc, San Francisco, CA, USA) and is often reported as a
benefit of full-dose psychedelics (Fadiman, 2011).
H2: Microdosers will have higher creativity scores than non-microdosers.
Importance of Benefits
Participants were asked to rate how important qualitative benefits of microdosing were to
them. We used this measure of subjective "importance of benefits” as a broad outcome of
participants' positive valuation of microdosing. Based on online anecdotal reports we predicted
that there would be a total-dose response curve such that microdosers would rate the importance
of benefits as quickly increasing to a plateau. Concerning dose scheduling, James Fadiman
(2011) proposed a dose-schedule such that microdosers consume their substance one day, then
refrain for two days, then dose again; we hypothesized that this schedule would show optimal
reported importance of benefits compared to alternate dose frequencies, perhaps due to
substance-tolerance (more frequent) or limited efficacy (less frequent).
Total Doses and Dose Frequency
H3a: A logarithmic relationship will exist between total lifetime microdoses and average
reported importance of benefits. Specifically, benefits are expected to be minimal with
minimal total doses, then increase, and subsequently stabilize at a plateau.
H3b: A quadratic relationship will exist between frequency of microdosing and average
reported importance of benefits. Specifically, maximum benefits are expected when
participants report frequency of microdoses at ~3 days between microdoses with reduced
benefits for shorter and longer frequencies.
More frequent and more intense positive experiences with a substance motivate future
use of that substance (de Wit and Phillips, 2012). As such, microdosers with a more extensive
history of full-dose psychedelic use may be especially motivated to try microdosing and may
evaluate benefits of microdosing more highly. This positivity bias may extend beyond
psychedelics as, more generally, substance use is associated with greater openness to experience
(Gunnarsson et al., 2008; Terracciano et al., 2008; Trull and Sher, 1994), which may include an
openness to try novel pharmacological interventions, such as microdosing.
Substance-Use History
H4a: Microdosers reporting at least one life-time use of a classic psychedelic (LSD,
psilocybin mushrooms, DMT, ayahuasca, mescaline) at full dose will report higher
average importance of benefits than microdosers that have not had a full dose.
H4b: Microdosers reporting greater variety of recreational substance use ("Polydrug user
experience index", see below) will report higher average importance of benefits than
microdosers with less recreational substance experience.
2.2 Deviations from Pre-Registration
A survey-flow error resulted in unintended data-collection on dose frequency and
importance (H3 and H4) from participants with no experience microdosing; this data has been
2.3 Participants
Participant were snowball-recruited via social media (e.g. Facebook, Twitter) and
recruited through posts on the online forum "reddit" (Reddit Inc, San Francisco, CA, USA): links
were posted under the username /u/oredna on the following subreddits: Microdosing, Nootropics,
Psychonaut, RationalPsychonaut, Tryptonaut, Drugs, LSD, shrooms, DMT, researchchemicals,
and SampleSize. Both participants with experience and participants without experience
microdosing psychedelics were recruited for this study. Participation was voluntary, and
participants were not remunerated. The survey was in English and internationally available.
Participants exited the online survey at different stages of completion; different analyses
therefore employ different numbers of participants. While 1390 respondents began the survey,
475 exited before responding, 3 requested that their responses be removed, and 3 responses were
removed for disingenuous responding, i.e. "trolling". In total 909 participants entered enough
data to be included in analyses, sorted into two categories: those with microdosing experience
(Microdosers: n = 594, 65%) and those without such experience (Non-microdosers: n = 315,
35%); full-dose experience with psychedelics was not considered for determining microdosing
status. Of these participants 29% were currently microdosing (current microdosers), 37% had
microdosed in the past but have since stopped (former microdosers), 30% were interested in
microdosing but had no prior experience, and 4% had no prior experience and reported not being
interested in microdosing. Participants from 29 countries responded to the survey (median age =
26, 82% males, 70% white). For a more comprehensive breakdown see the full epidemiological
report (Rosenbaum et al., 2018).
2.4 Design and Questionnaires
Following informed consent, participants completed online computer-based
questionnaires ( including questions pertaining to microdosing habits
(substance, frequency, dosage), substance use and mental health history, dispositional personality
variables (Dysfunctional Attitudes, Wisdom, Negative Emotionality, Open-Mindedness), and a
creativity task. Questions were displayed according to experience with microdosing, i.e.
individuals who reported never having microdosed were not shown questions related to a history
of microdosing (note survey flow error, 1.4.1 above). For uniformity, all scales were rated using
a continuous 0-100 slider-scale with nominal descriptors at 0 ("Disagree Strongly") and 100
("Agree Strongly") (Matejka et al., 2016). For brevity, methods reported here focus on variables
analyzed in this paper; a complete list of all questions is available on the OSF pre-registration.
2.4.1 Microdosing Substance
The majority of participants reported using LSD (65%) and/or Psilocybin (28%) for
microdosing; 16% reported using another substance. For a more comprehensive breakdown see
the full epidemiological report (Rosenbaum et al., 2018).
2.4.2 Mental Health Vulnerability
The DAS-A-17 is a short-version of the Dysfunctional Attitude Scale, a 40-item self-
report scale designed to measure the presence and intensity of dysfunctional beliefs (de Graaf et
al., 2009). Participants rate statements of beliefs (e.g. "If I fail at my work, then I am a failure as
a person.") on a 7-point Likert scale and the total score is the sum of the 17-items (range: 17
119) with higher scores indicating more dysfunctional attitudes (Weissman and Beck, 1978). The
DAS-A-17 includes a total-score and two subscales: "perfectionism/performance evaluation" (11
items) and "dependency" (6 items). Reliability for total score was excellent (α = 0.91) and good
for the subscales (perf: α = 0.87, dep: α = 0.85).
A Mental Health Index of psychological disorders was computed as a simple binary 0/1
based on the question, "Have you ever been diagnosed by a doctor or health care professional
(e.g., psychiatrist, psychologist) with any of the following diagnoses", which was followed by a
list of DSM-V diagnoses. Endorsing any diagnosis was coded as a "1", otherwise "None of the
above" was coded as "0". Comprehensive findings will be available in the epidemiological report
(Rosenbaum et al., 2018).
2.4.3 Wisdom
The Brief Wisdom Screening Scale (BWSS, Glück et al., 2013) was developed by
selecting the 20 items that were most highly correlated with the common factor of "wisdom self-
report" across three leading wisdom self-report measures. Reliability was good (α = 0.86).
2.4.4 Personality
The Big Five Inventory 2 (BFI2, Soto and John, 2016) is an updated five-factor
personality measure using the commonly recognized five-factor model: Extraversion,
Agreeableness, Conscientiousness, Negative Emotionality (formerly “Neuroticism”), and Open-
Mindedness (formerly Openness to Experience). Our hypotheses were centered on two of these
subscales: Negative Emotionality and Open-Mindedness, thus only these factors were measured.
Reliability was good (Negative Emotionality α = 0.91, Open-Mindedness α = 0.79).
2.4.5 Creativity
The Unusual Uses Task is a task in which participants generate creative uses for mundane
objects (UUT; Silvia, 2011). The UUT instructions emphasized the importance of original
responses, reading “Please try and think of the most unusual, creative, and uncommon uses you
can imagine” (Harrington, 1975). Participants were asked to give as many responses as they
could for each of two items (brick, knife), allotted one minute for each. During analysis,
responses were split into alphabetical lists to avoid within-participant biases. Responses were
rated by three independent research assistants using three dimensions: uncommon, clever, and
remote (Silvia et al., 2008). Dimension-scores across objects were averages to produce three
dimension-scores. Intraclass correlation coefficient was moderate for each dimension
(Uncommon: 68.25, Remote: 57.25, Clever: 59.75) and moderate for each object (brick = .61,
knife = .64).
2.4.6 Importance of Benefits
Participants rated qualitative benefits of microdosing in terms of personal, subjective
importance for three self-generated benefits. The average of these scores was then used as a
broad index of participants' subjective valuation of microdosing, analyzed in H3/4 in this study.
A taxonomy that organizes the participant-generated benefits has been generated using Grounded
Theory analysis and will be featured in an independent report (Anderson et al., 2018).
2.4.7 Microdosing Frequency
Microdosers reported the total number of lifetime microdoses taken (0 to 100). They also
reported dose scheduling, that is, the number of days spaced between each microdose (dose
every day to dose once every two months).
2.4.8 Substance-Use History
To test H4 concerning substance-use history, participants reported their experience with
full-dose psychedelics and with other substances. We developed a novel index: the "Polydrug
User Experience Index". This novel measure was computed as the sum of recreational
experiences across 13 classes of substance (e.g. Alcohol, Cannabis, MDMA, Stimulants, Opiates,
Dissociatives, etc.) accounting for recency of experience. Each class of substance was scored
according to the following metric: (a) used in past month: +4 points; (b) used in past year: +2
points; (c) used ever: +1 point; (d) never used: +0 points; (e) Prefer not to answer: +0 points.
Scores range from 052, with lower scores indicating less experience with recreational substance
2.4.9 Mood
A "Valence" score was computed using a mood-board ( as the count
of pleasant minus unpleasant items, as was an "Arousal" score for high-intensity minus low-
intensity moods.
3. Results
Table 1. Contrast between Microdosers and Non-Microdosers, means with standard deviations
and standardized effect-sizes.
27.23 (8.94)
26.36 (7.78)
4.72 (1.72)
4.78 (1.77)
0.50 (1.33)
0.51 (1.40)
Mood Valence
2.33 (4.40)
-0.16 (4.14)
Mood Intensity
-0.08 (2.42)
0.02 (2.40)
Dysfunctional Attitudes (DAS-17)3
40.62 (16.28)
49.30 (16.33)
Wisdom (BWSS)
66.68 (13.16)
60.05 (12.98)
Negative Emotionality (BFI-2)
41.53 (20.06)
48.16 (18.89)
Open-Mindedness (BFI-2)
76.43 (12.44)
73.33 (13.16)
1 Education was coded according to the International Standard Classification of Education (UNESCO
Institute for Statistics, 2011): ISCED level 0 = Early childhood education, 1 = Primary education, 2 =
Lower secondary education, 3 = Upper secondary education, 4 = Post-secondary non-tertiary education
Tertiary education, 5 = Short-cycle tertiary education, 6 = Bachelor’s or equivalent level, 7 = Master’s
or equivalent level, 8 = Doctoral or equivalent level
2 Socio-Economic Status (SES) was coded as: -3 = Non-working class (casual workers, pensioners, or
dependents); -2 = Working class (semi-skilled or unskilled manual workers); -1 = Skilled working class
(skilled manual workers); 0 = Lower-middle class (junior managerial, administrative, or professional); 1
= Middle class (intermediate managerial, administrative, or professional); 2 = Upper-middle class
(higher managerial, administrative, or professional); 3 = Upper class (royalty or immense heritable
3 DAS scores have been transformed to the original DAS-17 scale (17-119).
Table 2. Follow-up Analysis of Microdosers (Current versus Former), means with standard
deviations and standardized effect-sizes.
Effect size
d [95% CI]
28.89 (9.71)
25.93 (8.06)
0.33 [ 0.16 , 0.51 ]
4.83 (1.70)
4.64 (1.73)
0.11 [ -0.06 , 0.28 ]
0.48 (1.34)
0.52 (1.32)
-0.03 [ -0.2 , 0.14 ]
Mood Valence
2.93 (4.57)
1.86 (4.21)
0.24 [ 0.08 , 0.41 ]
Mood Intensity
0.10 (2.38)
-0.23 (2.45)
0.14 [ -0.03 , 0.3 ]
Dysfunctional Attitudes (DAS-17)
39.53 (14.58)
41.53 (17.56)
-0.12 [ -0.36 , 0.11 ]
Wisdom (BWSS)
66.09 (12.86)
67.18 (13.42)
-0.08 [ -0.32 , 0.15 ]
Negative Emotionality (BFI-2)
43.32 (19.98)
39.95 (20.07)
0.17 [ -0.06 , 0.4 ]
Open-Mindedness (BFI-2)
77.06 (11.91)
75.87 (12.91)
0.09 [ -0.13 , 0.32 ]
3.1 Pre-Registered Hypotheses and Planned Follow-up Analysis
3.1.1 Mental Health Vulnerability, Wisdom, and Personality
Mental Health Vulnerability. Microdosing predicted lower scores on Dysfunctional
Attitudes (b = -8.69, 95% CI [-12.48 -4.89], z(364) = -4.49, p < .001, r = -0.92), even when
controlling for a history of mental illness, which was also significant (b = 5.74, 95% CI [2.45
9.03], z(364) = 3.42, p < .001, r = 0.85) (Figure 2). Dysfunctional Attitudes were not related to
current versus former microdosing (b = 1.90, 95% CI [-1.91 5.71], p = 0.33), nor to type of
substance used (LSD vs Psilocybin: b = 0.56, 95% CI [-4.93 6.05], p = 0.842), nor to total
number of lifetime microdoses (b = -1.66, 95% CI [-3.47 0.15], p = 0.074).
Figure 2. Differences in dysfunctional attitudes between microdosers and non-microdosers
including breakdown by history of mental illness. The asterisk (*) indicates a significant main
effect of microdosing status such that microdosers showed lower dysfunctional attitudes than
non-microdosers (p < 0.001). Respondents with no history of mental illness (blue) also had lower
dysfunctional attitudes than those with a history of mental illness (orange, p < 0.001), though
microdosing status was a significant predictor even controlling for this potent covariate.
Wisdom. Microdosing predicted higher wisdom scores (b = 6.61, 95% CI [3.52 9.69],
z(367) = 4.19, p < .001, r = 0.88) when controlling for age and level of education, which were
not significant (age: b = -0.11, 95% CI [-0.26 0.04], p = 0.16, education: b = 0.40, 95% CI [-0.43
1.24], p = 0.35). No significant differences were found between current and former microdosers
(b = 1.09, 95% CI [-1.96 4.13], p = 0.48), nor type of substance used (b = 1.37, 95% CI [-2.83
5.57], p = .523), nor total lifetime number of microdoses (b = 0.62, 95% CI [-0.80 2.05], p =
Negative Emotionality. Microdosing predicted lower Negative Emotionality (b = -5.78,
95% CI [-10.13 -1.43], z(396) = -2.60, p = .009, r = -0.85), even after controlling for gender,
which was also a significant predictor (higher Negative Emotionality in females, b = 10.49, 95%
CI [5.33 15.65], z(396) = 3.99, p < .001, r = 0.95). Planned follow-up analysis tested the
difference between current and former microdosers and no significant difference existed between
the groups (b = -2.95, 95% CI [-7.47 1.58], p = 0.20), nor between substance used (b = -5.18,
95% CI [-11.50 1.15], p = .110), nor any effect of lifetime number of microdoses (b = -0.25, 95%
CI [-2.38 1.89], p = 0.82) on Negative Emotionality.
Open-Mindedness. Microdosing predicted greater Open-Mindedness (b = 3.24, 95% CI
[0.38 6.10], z(392) = 2.22, p = .027, r = 0.67), including when controlling for education, which
was not significant (b = 0.08, 95% CI [-0.65 0.81],p = 0.83). Again there were no significant
differences between current and former microdosers (b = -1.18, 95% CI [-4.00 1.64], p = 0.41),
nor type of substance used (b = 1.35, 95% CI [-2.61 5.31], p = .506), nor total lifetime number of
microdoses (b = 0.77, 95% CI [-0.55 2.09], p = 0.26).
3.1.2 Creativity
Microdosing predicted higher scores on all three creativity facets: on average, responses
made by microdosers were more clever (b = 0.57, SE = 0.13, z(423) = 4.25, p < .001, r = 0.15),
more uncommon (b = 0.50, SE = 0.15, z(427) = 3.42, p < .001, r = 0.14) and more remote (b =
0.74, SE = 0.16, z(425) = 4.49, p < .001, r = 0.20).
3.1.3 Importance of Benefits
Self-reported "importance of benefits” was intended to reflect participants' broad
valuation of microdosing. Counter to H3a/b, no significant differences were found in reported
importance of benefits when regressed on lifetime microdoses (b = 1.01, 95% CI [-0.81 2.82], p
= .277) nor frequency of microdosing regardless of explored linear and non-linear relationships
(raw: b = -0.07, 95% CI [-0.66 0.53], p = 0.83; squared: b = -0.0004, 95% CI [-0.01 0.01], p =
0.94; logarithmic: b = 1.21, 95% CI [-2.68 5.09],p = 0.54). Counter to H4a/b there were also no
significant difference in the importance of benefits between participants who had previous
experience with full-dose classic psychedelics and those who had no such experience (b = -4.09,
95% CI [-11.80 3.61], p = 0.30) nor based on the variety and recency of recreational substance
use (Polydrug User Experience Index: b = -0.006, 95% CI [-0.26 0.25], p = 0.96).
3.2 Exploratory Analysis
Exploratory comparison of mood measures (valence and intensity, Tables 1&2) by
Welch's t-test revealed that microdosers reported significantly more positive valence (M=2.33,
SD=4.40) than non-microdosers (M=-0.16, SD=4.14; difference: 2.49, 95% CI [1.91 3.07],
t(675) = 8.44, p < .001, r = 0.31). No differences were found for mood intensity (difference: -
0.11, 95% CI [-0.44 0.22] p = 0.53). For valence, current microdosers (M=2.93, SD=4.57) also
reported more positive valence than former microdosers (M=1.86, SD=4.21; difference: 1.07,
95% CI [0.35 1.79], t(533) = 2.92, p = .004, r = 0.13), but no difference in mood intensity
(difference: 0.33, 95% CI [-0.06 0.72], p = 0.10).
4. Discussion
This is the first preregistered report on microdosing psychedelics and is intended to
inform future lab-based clinical intervention studies. We investigated psychedelic microdosing in
online communities and tested pre-registered hypotheses (Anderson et al., 2017) concerning the
relationship between experience with microdosing and various mental health and personality
variables. Our results suggest a beneficial relationship wherein experience with microdosing is
associated with lower dysfunctional attitudes and negative emotionality and higher wisdom,
open-mindedness, and creativity. The most popular substances used to microdose were LSD and
psilocybin, and no significant differences based on substance were found on our quantitative
measures. The qualitative benefits and drawbacks collected in this survey may yet reveal
substance-based effects (Anderson et al., 2018). Hypotheses predicting perceived importance of
microdosing from dose-related practices were unsupported and optimal dose scheduling remains
an open question. Exploratory analyses revealed that microdosers, especially current
microdosers, had more positive emotional valence than non-microdosers, whereas emotional
intensity was not significantly different. Taken together, these findings suggest that randomized,
placebo-controlled clinical trials (RCTs) of microdosing are warranted to investigate the causal
efficacy of microdosing.
Consistent with our hypotheses, microdosing experience was associated with
meaningfully lower levels of dysfunctional attitudes. Individuals with higher dysfunctional
attitudes maintain a set of disadvantageous beliefs that increase vulnerability to stressors (Jarrett
et al., 2012) and high scores are associated with depression (Adler et al., 2015; de Graaf et al.,
2009). Also consistent with our hypotheses was the lower negative emotionality seen in
microdosers, though the estimated effect was less precise. Tendencies to experience negative
emotionality (e.g. anxiety, depression, emotional volatility) are a robust predictor of mental and
physical health problems (Lahey, 2009) thus reduced vulnerability is reflected in the lower
scores seen in microdosers. Exploratory analysis revealed that microdosers had more positive
emotional valence than non-microdosers, linking microdosing to better mood states. While
causation cannot be inferred from these results, significant differences were preserved even after
controlling for potent covariates, such as gender and history of mental illness, indicating a
potentially distinct contribution of microdosing on mental health vulnerability that warrants
further study.
Microdosers also had higher wisdom, which is a complex trait (BWSS, Glück et al.,
2013). As measured by the BWSS, wisdom is understood to reflect learning from one's mistakes,
considering multiple perspectives when facing a situation, being in tune with one's own emotions
and the emotions of others, and feeling a sense of connection and unity. Higher scores, as seen in
this sample of microdosers, may be associated with cognitive and emotional processing
differences including enhanced capacity for perspective taking, resilience in the face of the
vicissitudes of life, and increased feelings of engagement and connection. RCT research
addressing the relationship between wisdom and microdosing are warranted.
Greater open-mindedness was expected in microdosers compared to controls due to
previous studies noting increases in openness following a full-dose of psilocybin (MacLean,
Johnson, & Griffiths, 2011). These differences were supported, though this effect was relatively
weaker than the others. Still, given the findings from full-dose psychedelic studies, future clinical
intervention research should continue investigating any causal relationship between open-
mindedness and microdosing.
Microdosers were more creative when finding unusual uses for household items. This is
consistent with Fredrickson's (2004) Broaden and Build theory, which suggests a positive
relationship between creativity and positive affect, which was also seen in microdosers. Happier,
more creative people may be more likely to apply novel modes of thinking in their personal and
interpersonal challenges (Fredrickson, 2004). Our findings are also consistent with the anecdotal
reports that a relationship between microdosing, creativity, and mood exists, but RCTs, ideally
with multiple creativity measures, are required.
None of our hypotheses concerning the importance of microdosing benefits and
microdosing practices were supported. It is likely that this measure was not sensitive and specific
enough; planned analyses of qualitative benefits and drawbacks of microdosing will be explored
in a separate report (Anderson et al., 2018). It may be that microdosing frequency is truly
unrelated to the subjective valuation of microdosing, but this seems improbable. We suggest that
this research question is best addressed in RCT studies focused on specific benefits with
experimental manipulation of dose and schedule to determine optimal benefit-specific protocols.
Similarly, there is no evidence that outcomes are predicated on prior experience with substances,
whether full-dose psychedelics or with a variety of substances. More microdosers had experience
with full-doses (69%, n=412) then did not (31%, n=182) and many microdosers (and non-
microdosers) had experience with full-dose psychedelics within the month prior to completing
the survey. As full-dose psychedelics can have benefits lasting at least a month (Carhart-Harris et
al., 2017) this covariate should be formally modelled in future microdosing research designs,
which should aim to include both psychedelic-naïve and psychedelic-experienced participants.
5. Limitations and Future Directions
The sample is both a strength and a limitation of this study. This sample represents a true
community of microdosers with dozens of countries represented, however, countries in the
Anglo cultural cluster make up the majority of the sample (>70%) and participants were
predominantly middle-class, white, male, and heterosexual. Sampling from online communities,
including Reddit, could create a demographic bias thus we cannot suggest a definitive
epidemiological generalization. Despite this limitation, this sample does inform us about real
community practices in an otherwise unstudied population and reflects our sample of interest.
A second limitation of this study is its correlational nature. This cross-sectional design
contained no longitudinal component or experimental manipulation and cannot be used to infer
causal relationships. Our findings of group-differences do not infer that microdosing caused
these differences as some of the measured constructs may even promote an increased willingness
to explore microdosing, e.g. open-mindedness. Instead, these findings are intended as a
descriptive foundation upon which experimental and clinical studies of psychedelic microdosing
can be designed, exploring the directionality of relationships established in the present study.
To test causal hypotheses concerning microdosing effects, pre-registered randomized
placebo-control trials (RCTs) are needed. With random assignment to microdose or placebo it
would be possible to determine whether microdosing causally influences mental health and
personality. Following positive causal findings, mechanistic studies could then investigate the
observed efficacy in terms of physiological, psychological, and neurobiological changes.
Promisingly, microdosing may prove easier to administer, monitor, and placebo-control
in lab settings due to the absence of the intense perceptual shifts induced by full-doses.
Microdosing may thus be amenable to designs that could aid in mapping the neural mechanisms
behind psychedelic efficacy. Microdosing could also be explored as an adjunct to long-term
psychotherapy predicated on the longitudinal cultivation of resilience and insight, a new
paradigm that could compliment the acutely transformative model underlying high-dose
psychedelic psychotherapy (Rosenbaum et al., 2018).
6. Conclusion
This study provides initial, correlational evidence for mental health and personality
benefits associated with microdosing psychedelics. While anecdotal reports of microdosing
benefits have existed for some time (Fadiman, 2011), this study marks the first formal study of
the topic. Additionally, the use of a pre-registered study design sets a precedent for responsible
and replicable psychedelic microdosing research. To add depth to the current discussion, a full
epidemiological report (Rosenbaum et al., 2018) and a Grounded Theory analysis of qualitative
outcomes (Anderson et al., 2018) are forthcoming.
The results of the present study suggest that there is a significant relationship between
microdosing experience and measures of mental health and flourishing including lower
dysfunctional attitudes and negative emotionality, higher wisdom and open-mindedness, and
higher creativity and affect-valence. These findings are the initial evidence that warrants RCTs to
directly test safety and therapeutic efficacy. With almost 40,000 users subscribing to the
/r/microdosing subreddit and thousands more reading media reports on microdosing this growing
community continues to explore microdosing and its effects. It is our hope that scientific
reporting can help to clarify and inform the public about the nature of microdosing’s putative
effects and that this new paradigm helps shape future psychedelic research. We hope that
researchers will draw on our shared resources ( and pre-register studies of
their own so that psychedelic science will be built upon strong research practices. Insights from
these and other studies will form the backbone of future research into microdosing psychedelics
Conflict of interest statement
On behalf of all authors, the corresponding author states that there is no conflict of interest.
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... Furthermore, there is anecdotal evidence supporting that microdosing psychedelics can increase creativity and problem-solving abilities, as well as promote cognitive flexibility and positively affect empathy and reduce levels of mind wandering [8,[17][18][19]. Some individuals microdose to selfmedicate for cluster headaches, depression and anxiety, among other conditions [20][21][22]. Indeed, it has been proposed that microdosing with psychedelics could have therapeutic value for the treatment of mental health disorders [23]. The use of low doses of psychedelics constitutes an attractive therapeutic model, since it could circumvent the potential issues associated with altered consciousness and challenging experiences elicited by higher doses [24]. ...
... The logarithmic power spectral density (LPSD) in the delta (1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), beta (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) and gamma (30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40) bands was computed for each subject, condition and channel using a fast Fourier transform with a Hanning-tapered window (EEGLAB). ...
... As expected, the power spectra for eyes closed show a peak close to 10 Hz, which is attenuated in the eyes open condition. The psilocybin mushroom microdose resulted in decreased power in the theta range (4 to 8 Hz). Figure 4B presents the same results binned into four major frequency bands: delta (1-4 Hz), theta (4-8 Hz), alpha (8)(9)(10)(11)(12) and beta (12)(13)(14)(15)(16)(17)(18)(19)(20). Consistent with the spectra shown in Fig. 4A, only the eyes closed theta band power decreased under the active dose compared to the placebo (p < 0.05, both uncorrected and Bonferroni corrected with n = 4). ...
Full-text available
The use of low sub-perceptual doses of psychedelics (“microdosing”) has gained popularity in recent years. Although anecdotal reports claim multiple benefits associated with this practice, the lack of placebo-controlled studies severely limits our knowledge of microdosing and its effects. Moreover, research conducted in standard laboratory settings could fail to capture the motivation of individuals engaged or planning to engage in microdosing protocols, thus underestimating the likelihood of positive effects on creativity and cognitive function. We recruited 34 individuals starting to microdose with psilocybin mushrooms (Psilocybe cubensis), one of the materials most frequently used for this purpose. Following a double-blind placebo-controlled experimental design, we investigated the acute and short-term effects of 0.5 g of dried mushrooms on subjective experience, behavior, creativity (divergent and convergent thinking), perception, cognition, and brain activity. The reported acute effects were significantly more intense for the active dose compared to the placebo, but only for participants who correctly identified their experimental condition. These changes were accompanied by reduced EEG power in the theta band, together with preserved levels of Lempel-Ziv broadband signal complexity. For all other measurements there was no effect of microdosing except for few small changes towards cognitive impairment. According to our findings, low doses of psilocybin mushrooms can result in noticeable subjective effects and altered EEG rhythms, but without evidence to support enhanced well-being, creativity and cognitive function. We conclude that expectation underlies at least some of the anecdotal benefits attributed to microdosing with psilocybin mushrooms.
... Improved mood associated with microdosing was found across numerous qualitative (Anderson et al., 2019a;Fadiman & Korb, 2019;Johnstad, 2018;Lea et al., 2020a;Webb et al., 2019), retrospective survey (Anderson et al., 2019b;Hutten et al., 2019a;Lea et al., 2020b;Petranker, Anderson, Maier, et al., 2020), prospective (Szigeti et al., 2021), and lab ...
... Improvements in substance misuse was another recurrent finding, although this was assessed in only a minority of studies. Qualitative studies showed microdosing was thought by respondents to be linked to reductions in smoking (Johnstad, 2018), and substance use (Anderson et al., 2019b;Webb et al., 2019). Additionally, one retrospective survey study found that microdosers reported lower levels of substance use disorders yet higher rates of recreational substance use (Rosenbaum et al., 2020). ...
... Three qualitative studies (Anderson et al., 2019b;Beaton et al., 2020;Webb et al., 2019), and one retrospective survey study showed increases in the overlapping constructs of wellbeing, self-fulfilment, self-efficacy, and resilience. ...
The use of low doses of psychedelic substances (microdosing) is attracting increasing interest. This systematic review summarises all empirical microdosing research to date, including a set of infrequently cited studies that took place prior to prohibition. Specifically, we reviewed 44 studies published between 1955 and 2021, and summarised reported effects across six categories: mood and mental health; wellbeing and attitude; cognition and creativity; personality; changes in conscious state; and neurobiology and physiology. Studies showed a wide range in risk of bias, depending on design, age, and other study characteristics. Laboratory studies found changes in pain perception, time perception, conscious state, and neurophysiology. Self-report studies found changes in cognitive processing and mental health. We review data related to expectation and placebo effects, but argue that claims that microdosing effects are largely due to expectancy are premature and possibly wrong. In addition, we attempt to clarify definitional inconsistencies in the microdosing literature by providing suggested dose ranges across different substances. Finally, we provide specific design suggestions to facilitate more rigorous future research.
... Surveys of microdosing psilocybin have identified diverse practices but generally converge on the self-administration, 3-5 times per week, of 0.1 to 0.3 g of dried mushrooms [7][8][9][10][11][12] . Improvements in mood, emotional well-being and cognition have been reported among the top motivations for microdosing 13 , and several cross-sectional studies have identified associations between microdosing and perceived improvements in mood [13][14][15][16][17] and cognitive functioning 10,11,16 , reductions in stress 7 , depression 7,9,16 and anxiety 7,9,14,18 . ...
... Surveys of microdosing psilocybin have identified diverse practices but generally converge on the self-administration, 3-5 times per week, of 0.1 to 0.3 g of dried mushrooms [7][8][9][10][11][12] . Improvements in mood, emotional well-being and cognition have been reported among the top motivations for microdosing 13 , and several cross-sectional studies have identified associations between microdosing and perceived improvements in mood [13][14][15][16][17] and cognitive functioning 10,11,16 , reductions in stress 7 , depression 7,9,16 and anxiety 7,9,14,18 . ...
Full-text available
Psilocybin microdosing involves repeated self-administration of mushrooms containing psilocybin at doses small enough to not impact regular functioning. Microdose practices are diverse and include combining psilocybin with substances such as lion's mane mushrooms (Hericium erinaceus; HE) and niacin (vitamin-B3). Public uptake of microdosing has outpaced evidence, mandating further prospective research. Using a naturalistic, observational design, we followed psilocybin microdosers (n = 953) and non-microdosing comparators (n = 180) for approximately 30 days and identified small-to medium-sized improvements in mood and mental health that were generally consistent across gender, age and presence of mental health concerns, as we all as improvements in psychomotor performance that were specific to older adults. Supplementary analyses indicated that combining psilocybin with HE and B3 did not impact changes in mood and mental health. However, among older microdosers combining psilocybin, HE and B3 was associated with psychomotor improvements relative to psilocybin alone and psilocybin and HE. Our findings of mood and mental health improvements associated with psilocybin microdosing add to previous studies of psychedelic microdosing by using a comparator group and by examining the consistency of effects across age, gender, and mental health. Findings regarding the combination of psilocybin, HE and B3 are novel and highlight the need for further research to confirm and elucidate these apparent effects.
... Apart from cognitive impairment, researchers have also taken interest in evaluating the possible cognitive enhancement properties of psychedelics, which has long motivated consuming psychedelics in popular culture and was recently suggested to have a positive role clinically, such as facilitated psychotherapy [126,127]. The two studies assessing the cognitive enhancement potential of psilocybin showed improvements in cognitive abilities such as autobiographical memory and creative thinking [42,106]. ...
Full-text available
Background Preliminary results from randomized controlled studies as well as identified molecular, cellular, and circuit targets of select psychedelics (e.g., psilocybin) suggest that their effects are transdiagnostic. In this review, we exploit the Research Domain Criteria (RDoC) transdiagnostic framework, to synthesize extant literature on psilocybin.Objective We aimed to identify RDoC-based effects of psilocybin and vistas for future mechanistic and interventional research.MethodsA systematic search in electronic databases (i.e., PubMed, Scopus, PsycINFO, and Web of Science) performed in January and February 2021 identified English articles published between 1990 and 2020 reporting the effects of psilocybin on mental health measures. Data from included articles were retrieved and organized according to the RDoC bio-behavioral matrix and its constituent six main domains, namely: positive valence systems, negative valence systems, cognitive systems, social processes, sensorimotor systems, and arousal and regulatory systems.ResultsThe preponderance of research with psilocybin has differentially reported beneficial effects on positive valence systems, negative valence system, and social process domains. The data from the included studies support both short-term (23 assessments) and long-term (15 assessments) beneficial effects of psilocybin on the positive valence systems. While 12 of the extracted outcome measures suggest that psilocybin use is associated with increases in the “fear” construct of the negative valence systems domain, 19 findings show no significant effects on this construct, and seven parameters show lowered levels of the “sustained threat” construct in the long term. Thirty-four outcome measures revealed short-term alterations in the social systems’ construct namely, “perception and understanding of self,” and “social communications” as well as enhancements in “perception and understanding of others” and “affiliation and attachment”. The majority of findings related to the cognitive systems’ domain reported dyscognitive effects. There have been relatively few studies reporting outcomes of psilocybin on the remaining RDoC domains. Moreover, seven of the included studies suggest the transdiagnostic effects of psilocybin. The dashboard characterization of RDoC outcomes with psilocybin suggests beneficial effects in the measures of reward, threat, and arousal, as well as general social systems.Conclusions Psilocybin possesses a multi-domain effectiveness. The field would benefit from highly rigorous proof-of-mechanism research to assess the effects of psilocybin using the RDoC framework. The combined effect of psilocybin with psychosocial interventions with RDoC-based outcomes is a priority therapeutic vista.
... In addition to the single-injection protocol, we investigated the effect of a microdosing-like strategy on body weight (Fig. 2G). Psychedelic microdosing has been popularized for its benefits on creativity, problem-solving ability, and energy levels [50,51]. In a separate cohort of DIO mice, intraperitoneal injection of psilocybin (0.3 mg/kg) or vehicle was administered daily. ...
Full-text available
Psilocybin and other serotonergic psychedelics have re-emerged as therapeutics for neuropsychiatric disorders, including addiction. Psilocybin induces long-lasting effects on behavior, likely due to its profound ability to alter consciousness and augment neural connectivity and plasticity. Impaired synaptic plasticity in obesity contributes to ‘addictive-like’ behaviors, including heightened motivation for palatable food, and excessive food seeking and consumption. Here, we evaluate the effects of psilocybin on feeding behavior, energy metabolism, and as a weight-lowering agent in mice. We demonstrate that a single dose of psilocybin substantially alters the prefrontal cortex transcriptome but has no acute or long-lasting effects on food intake or body weight in diet-induced obese mice or in genetic mouse models of obesity. Similarly, sub-chronic microdosing of psilocybin has no metabolic effects in obese mice and psilocybin does not augment glucagon-like peptide-1 (GLP-1) induced weight loss or enhance diet-induced weight loss. A single high dose of psilocybin reduces sucrose preference but fails to counter binge-like eating behavior. Although these preclinical data discourage clinical investigation, there may be nuances in the mode of action of psychedelic drugs that are difficult to capture in rodent models, and thus require human evaluation to uncover.
... Current research concerning the effects of microdosing has focused on determining dose-effect relationships (Bershad et al. 2019;Holze et al. 2020;Hutten et al. 2020) or patterns of use and associated outcomes (Andersson and Kjellgren 2019;Hutten et al. 2019;Johnstad 2018;Webb, Copes, and Hendricks 2019). Findings have been inconclusive, with some studies observing that microdosing is associated with improved mental health (Anderson et al. 2019) and others observing increased anxiety in microdosers compared to controls Hutten et al. 2020). ...
While anecdotal reports claim that psychedelic microdosing reduces anxiety and mood symptoms, evidence supporting these claims is scarce. This cross-sectional study investigated the association between microdosing and trait anxiety. Furthermore, it was investigated if trait mindfulness mediated this association. Participants completed anonymous online questionnaires and were divided into three groups: current microdosers (n = 186), former microdosers (n = 77) and microdosing-naïve controls (n = 234). Trait anxiety and trait mindfulness were measured using the State-Trait Anxiety Inventory - Trait subscale (STAI-T) and the 15-item Five-Facet Mindfulness Questionnaire (FFMQ-15) respectively. Current and former microdosers reported lower STAI-T scores compared to microdosing-naïve controls. Furthermore, associations of current and former microdosing with trait anxiety were mediated by trait mindfulness, with small effects of FFMQ-15 Total, Non-judging and Non-reactivity scores. However, in an exploratory analysis, all associations between microdosing and STAI-T scores became non-significant when participants with previous macrodose experience (n = 386) were excluded. Our findings suggest that RCT<apos;>s are warranted to test causal hypotheses concerning the effects of microdosing and the role of trait mindfulness in the effects of microdosing, while controlling for previous macrodose experience.
To date, the clinical and scientific literature has best documented the effects of classical psychedelics, such as lysergic acid diethylamide (LSD), psilocybin, and dimethyltryptamine (DMT), in typical quantities most often associated with macrodosing. More recently, however, microdosing with psychedelics has emerged as a social trend and nascent therapeutic intervention. This variation in psychedelic practice refers to repeat, intermittent ingestion of less-than-macrodose amounts that do not cause the effects associated with full-blown “trips”. Microdosing paves the road to incorporating psychedelic drugs into a daily routine while maintaining, or even improving, cognitive and mental function. Unlike macrodosing with psychedelics, the influence of microdosing remains mostly unexplored. And yet, despite the paucity of formal studies, many informal accounts propose that microdosing plays an important role as both a therapeutic intervention (e.g., in mental disorders) and enhancement tool (e.g., recreationally—to boost creativity, improve cognition, and drive personal growth). In response to this relatively new practice, we provide an integrative synthesis of the clinical, social, and cultural dimensions of microdosing. We describe some of the overarching context that explains why this practice is increasingly in vogue, unpack potential benefits and risks, and comment on sociocultural implications. In addition, this article considers the effects that macro- and microdoses have on behavior and psychopathology in light of their dosage characteristics and contexts of use.
Background and aims: Hallucinogen use is potentially harmful. Information on whether such use has increased in recent decades is lacking. This study assessed overall and age-specific time trends in the prevalence of 12-month hallucinogen use in the US general population. Design: Cross-sectional. Setting: Data from the US National Survey on Drug Use and Health, 2002-19. Participants: Respondents aged ≥ 12 years (n = 1 006 051). Measurements: Predictors were continuous years. Outcome variables included any hallucinogen use and use of lysergic acid diethylamide (LSD), ecstasy and phencyclidine (PCP) in the past year. Socio-demographic variables (gender, age, race/ethnicity, educational level and family income) were covariates. Findings: Overall, hallucinogen use increased between 2015 and 2019 [prevalence difference (PD) = +0.44, P < 0.05]. Since 2002, hallucinogen use has increased in adults aged ≥ 26 years (PD, 2002-14 = +0.24, P < 0.05; PD, 2015-19 = +0.45, P < 0.001) and decreased in adolescents aged 12-17 years (PD, 2002-14 = -1.60, P < 0.0001; PD, 2015-19 = -0.73, P < 0.001). Ecstasy use has decreased in adolescents (PD, 2002-14 = -0.56, P < 0.001), adults aged 18-25 years (PD, 2015-19 = -0.96, P < 0.01) and ≥ 26 years (PD, 2015-19 = -0.13, P < 0.05). LSD use between 2002 and 2019 increased overall (PD = +0.71, P < 0.0001) and in all age groups (12-17: PD = +0.67, P < 0.001; 18-25: PD = +3.12, P < 0.0001; ≥ 26: PD = +0.36, P < 0.0001). Conversely, PCP use between 2002 and 2019 decreased overall (PD = -0.06, P < 0.001), in adolescents (PD = -0.24, P < 0.001) and young adults (PD = -0.32, P < 0.0001). Conclusions: Since 2002, hallucinogen use in the United States has decreased among adolescents but increased in adults and is now estimated to affect more than 3 million adults aged 26+ years and more than 5.5 million adults aged 18+ years.
This integrative review was conducted to summarize the knowledge pertaining to the effects that serotonergic psychedelics can have on creativity, a multi-dimensional construct referring to the ability to produce original and valuable artifacts. Psychedelics, which have long been hailed as substances that can enhance the creative process in their users, have experienced a recent resurgence in research, allowing the opportunity to better understand this relationship. To this end, I reviewed literature which attempted to study the effects of serotonergic psychedelics on creativity through psychometric methods. A total of eleven studies were reviewed, with four psychedelic compounds represented. Every study assessed components and subcomponents of divergent and convergent thinking, with only one instance of product assessment. Results suggest that convergent thinking may increase during the post-acute phases of the drugs' intake, fostering the capacity for development of previously generated ideas. However, this evidence may be circumstantial based on the low number of studies available, small sample sizes, overall lack of randomized controlled trials, and significant methodological limitations throughout most studies. Potential mechanisms underlying these effects are discussed, along with the current state of the research and implications for future studies.
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Rationale: Serotonergic psychedelics are being studied as novel treatments for mental health disorders and as facilitators of improved well-being, mental function, and creativity. Recent studies have found mixed results concerning the effects of low doses of psychedelics ("microdosing") on these domains. However, microdosing is generally investigated using instruments designed to assess larger doses of psychedelics, which might lack sensitivity and specificity for this purpose. Objectives: Determine whether unconstrained speech contains signatures capable of identifying the acute effects of psilocybin microdoses. Methods: Natural speech under psilocybin microdoses (0.5 g of psilocybin mushrooms) was acquired from thirty-four healthy adult volunteers (11 females: 32.09 ± 3.53 years; 23 males: 30.87 ± 4.64 years) following a double-blind and placebo-controlled experimental design with two measurement weeks per participant. On Wednesdays and Fridays of each week, participants consumed either the active dose (psilocybin) or the placebo (edible mushrooms). Features of interest were defined based on variables known to be affected by higher doses: verbosity, semantic variability, and sentiment scores. Machine learning models were used to discriminate between conditions. Classifiers were trained and tested using stratified cross-validation to compute the AUC and p-values. Results: Except for semantic variability, these metrics presented significant differences between a typical active microdose and the inactive placebo condition. Machine learning classifiers were capable of distinguishing between conditions with high accuracy (AUC [Formula: see text] 0.8). Conclusions: These results constitute first evidence that low doses of serotonergic psychedelics can be identified from unconstrained natural speech, with potential for widely applicable, affordable, and ecologically valid monitoring of microdosing schedules.
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The Benefits and Drawbacks of Microdosing Psychedelics Microdosing psychedelics is the practice of taking very low doses of psychedelic substances (e.g. LSD, psilocybin). Psychedelic microdosing has recently been featured in numerous popular-media reports yet no scientific studies have been published on this topic. At present only anecdotes regarding the effects of microdosing are discussed and these have not been described in the scientific literature. To address these literature gaps we ran the first pre-registered scientific study on microdosing psychedelics by investigating the practices of online communities already engaging in this activity. This pre-registered online study collected 1034 benefits and 791 drawbacks drawn from 577 participants. These data were subjected to classic Grounded Theory analysis and a number of highly relevant conceptual groupings of benefits and drawbacks emerged. By discussing these groupings and suggesting psychometric measures intended to assess these outcomes this lecture will provide researchers with tangible suggestions for incorporating relevant measures into their psychedelic studies. We will also make recommendations that inform the non-academic community about the potential outcomes of microdosing with added focus on harm-reduction. This research informs both the individuals already microdosing and the scientific community intending to study microdosing and psychedelic outcomes in the future.
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Conclusions: (1) psilocybin has an abuse potential appropriate for CSA scheduling if approved as medicine; (2) psilocybin can provide therapeutic benefits that may support the development of an approvable New Drug Application (NDA) but further studies are required which this review describes; (3) adverse effects of medical psilocybin are relatively low and manageable when administered according to risk management approaches; and (4) although further study is required, this review suggests that placement in Schedule IV may be appropriate if a psilocybin-containing medicine is approved.
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Hallucinogen Persisting Perception Disorder (HPPD) is a rare, and therefore, poorly understood condition linked to hallucinogenic drugs consumption. The prevalence of this disorder is low; the condition is more often diagnosed in individuals with a history of previous psychological issues or substance misuse, but it can arise in anyone, even after a single exposure to triggering drugs. The aims of the present study are to review all the original studies about HPPD in order to evaluate the following: (1) the possible suggested etiologies; (2) the possible hallucinogens involved in HPPD induction; (3) the clinical features of both HPPD I and II; (4) the possible psychiatric comorbidities; and (5) the available and potential therapeutic strategies. We searched PubMed to identify original studies about psychedelics and Hallucinogen Persisting Perception Disorder (HPPD). Our research yielded a total of 45 papers, which have been analyzed and tabled to provide readers with the most updated and comprehensive literature review about the clinical features and treatment options for HPPD.
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Psilocybin with psychological support is showing promise as a treatment model in psychiatry but its therapeutic mechanisms are poorly understood. Here, cerebral blood flow (CBF) and blood oxygen-level dependent (BOLD) resting-state functional connectivity (RSFC) were measured with functional magnetic resonance imaging (fMRI) before and after treatment with psilocybin (serotonin agonist) for treatment-resistant depression (TRD). Quality pre and post treatment fMRI data were collected from 16 of 19 patients. Decreased depressive symptoms were observed in all 19 patients at 1-week post-treatment and 47% met criteria for response at 5 weeks. Whole-brain analyses revealed post-treatment decreases in CBF in the temporal cortex, including the amygdala. Decreased amygdala CBF correlated with reduced depressive symptoms. Focusing on a priori selected circuitry for RSFC analyses, increased RSFC was observed within the default-mode network (DMN) post-treatment. Increased ventromedial prefrontal cortex-bilateral inferior lateral parietal cortex RSFC was predictive of treatment response at 5-weeks, as was decreased parahippocampal-prefrontal cortex RSFC. These data fill an important knowledge gap regarding the post-treatment brain effects of psilocybin, and are the first in depressed patients. The post-treatment brain changes are different to previously observed acute effects of psilocybin and other ‘psychedelics’ yet were related to clinical outcomes. A ‘reset’ therapeutic mechanism is proposed.
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Cancer patients often develop chronic, clinically significant symptoms of depression and anxiety. Previous studies suggest that psilocybin may decrease depression and anxiety in cancer patients. The effects of psilocybin were studied in 51 cancer patients with life-threatening diagnoses and symptoms of depression and/or anxiety. This randomized, double-blind, cross-over trial investigated the effects of a very low (placebo-like) dose (1 or 3 mg/70 kg) vs. a high dose (22 or 30 mg/70 kg) of psilocybin administered in counterbalanced sequence with 5 weeks between sessions and a 6-month follow-up. Instructions to participants and staff minimized expectancy effects. Participants, staff, and community observers rated participant moods, attitudes, and behaviors throughout the study. High-dose psilocybin produced large decreases in clinician- and self-rated measures of depressed mood and anxiety, along with increases in quality of life, life meaning, and optimism, and decreases in death anxiety. At 6-month follow-up, these changes were sustained, with about 80% of participants continuing to show clinically significant decreases in depressed mood and anxiety. Participants attributed improvements in attitudes about life/self, mood, relationships, and spirituality to the high-dose experience, with >80% endorsing moderately or greater increased well-being/life satisfaction. Community observer ratings showed corresponding changes. Mystical-type psilocybin experience on session day mediated the effect of psilocybin dose on therapeutic outcomes. Trial Registration identifier: NCT00465595
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Background: Clinically significant anxiety and depression are common in patients with cancer, and are associated with poor psychiatric and medical outcomes. Historical and recent research suggests a role for psilocybin to treat cancer-related anxiety and depression. Methods: In this double-blind, placebo-controlled, crossover trial, 29 patients with cancer-related anxiety and depression were randomly assigned and received treatment with single-dose psilocybin (0.3 mg/kg) or niacin, both in conjunction with psychotherapy. The primary outcomes were anxiety and depression assessed between groups prior to the crossover at 7 weeks. Results: Prior to the crossover, psilocybin produced immediate, substantial, and sustained improvements in anxiety and depression and led to decreases in cancer-related demoralization and hopelessness, improved spiritual wellbeing, and increased quality of life. At the 6.5-month follow-up, psilocybin was associated with enduring anxiolytic and anti-depressant effects (approximately 60-80% of participants continued with clinically significant reductions in depression or anxiety), sustained benefits in existential distress and quality of life, as well as improved attitudes towards death. The psilocybin-induced mystical experience mediated the therapeutic effect of psilocybin on anxiety and depression. Conclusions: In conjunction with psychotherapy, single moderate-dose psilocybin produced rapid, robust and enduring anxiolytic and anti-depressant effects in patients with cancer-related psychological distress. Trial registration: Identifier: NCT00957359.
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Acute and enduring adverse effects of psilocybin have been reported anecdotally, but have not been well characterized. For this study, 1993 individuals (mean age 30 yrs; 78% male) completed an online survey about their single most psychologically difficult or challenging experience (worst “bad trip”) after consuming psilocybin mushrooms. Thirty-nine percent rated it among the top five most challenging experiences of his/her lifetime. Eleven percent put self or others at risk of physical harm; factors increasing the likelihood of risk included estimated dose, duration and difficulty of the experience, and absence of physical comfort and social support. Of the respondents, 2.6% behaved in a physically aggressive or violent manner and 2.7% received medical help. Of those whose experience occurred >1 year before, 7.6% sought treatment for enduring psychological symptoms. Three cases appeared associated with onset of enduring psychotic symptoms and three cases with attempted suicide. Multiple regression analysis showed degree of difficulty was positively associated, and duration was negatively associated, with enduring increases in well-being. Difficulty of experience was positively associated with dose. Despite difficulties, 84% endorsed benefiting from the experience. The incidence of risky behavior or enduring psychological distress is extremely low when psilocybin is given in laboratory studies to screened, prepared, and supported participants.
Conference Paper
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Sliders and Visual Analogue Scales (VASs) are input mechanisms which allow users to specify a value within a predefined range. At a minimum, sliders and VASs typically consist of a line with the extreme values labeled. Additional decorations such as labels and tick marks can be added to give information about the gradations along the scale and allow for more precise and repeatable selections. There is a rich history of research about the effect of labelling in discrete scales (i.e., Likert scales), however the effect of decorations on continuous scales has not been rigorously explored. In this paper we perform a 2,000 user, 250,000 trial online experiment to study the effects of slider appearance, and find that decorations along the slider considerably bias the distribution of responses received. Using two separate experimental tasks, the trade-offs between bias, accuracy, and speed-of-use are explored and design recommendations for optimal slider implementations are proposed.
Rationale Microdosing psychedelics – the practice of consuming small, sub-hallucinogenic doses of substances such as LSD or psilocybin – is gaining attention in popular media but remains poorly characterized. Contemporary studies of psychedelic microdosing have yet to report the basic psychiatric descriptors of psychedelic microdosers. Objectives To examine the practices and demographics of a population of psychedelic microdosers – including their psychiatric diagnoses, prescription medications, and recreational substance use patterns – to develop a foundation on which to conduct future clinical research. Methods Participants ( n = 909; M age = 26.9, SD = 8.6; male = 83.2%; White/European = 79.1%) recruited primarily from the online forum Reddit completed an anonymous online survey. Respondents who reported using LSD, psilocybin, or both for microdosing were grouped and compared with non-microdosing respondents using exploratory odds ratio testing on demographic variables, rates of psychiatric diagnoses, and past-year recreational substance use. Results Of microdosers, most reported using LSD (59.3%; M dose = 13 mcg, or 11.3% of one tab) or psilocybin (25.9%; M dose = 0.3 g of dried psilocybin mushrooms) on a one-day-on, two-days-off schedule. Compared with non-microdosers, microdosers were significantly less likely to report a history of substance use disorders (SUDs; OR = 0.17 (95% CI: 0.05–0.56)) or anxiety disorders (OR = 0.61 (95% CI: 0.41–0.91)). Microdosers were also more likely to report recent recreational substance use compared with non-microdosers (OR = 5.2 (95% CI: 2.7–10.8)). Conclusions Well-designed randomized controlled trials are needed to evaluate the safety and tolerability of this practice in clinical populations and to test claims about potential benefits.
Use of hallucinogenic substances as a public health concern has increased over the past decade. Among adolescents, there are increasing emergency department presentations for intoxication with these drugs, contrary to decreasing reported use of classical hallucinogens such as LSD. Academic and governmental groups have monitored use of hallucinogens, highlighting a notable change in perceptions about use among adolescents thought to contribute to these trends. Special populations and religious groups, though, have been granted governmental permission to use hallucinogens for their cultural practices. Novel designer hallucinogens have gained popularity and may have serious medical and psychological side effects from use.