Changed Substance Use After Psychedelic Experiences Among Individuals in Canada

Abstract

We conducted a cross-sectional online survey of adults (n = 1639; 56.3% women) self-reporting past or current psychedelic use. We investigated whether psychedelic use was associated with self-reported changes in the use of other substances. Participants reported substantial changes, with 43.8% (n = 651/1488) decreasing or ceasing alcohol use, 42.5% (n = 272/640) ceasing or decreasing antidepressant use, and 42.4% (n = 200/471) decreasing or ceasing cocaine use. The highest rates of increased use were for cannabis (10.9%; n = 151/1383) and tobacco products (9.3%; n = 60/646). The most common reasons for substance use reductions were feeling more connected with self (73%; n = 632), nature (55%; n = 476), and others (54.6%; n = 473), as well as feeling less anxious or depressed (59.4%; n = 514). Factors associated with reduction in any substance use included motivation to treat a medical condition, number of psychedelics used, younger age, and using both microdoses and macrodoses. This real-world evidence should be rigorously investigated in future studies.

Full text

Vol.:(0123456789)
International Journal of Mental Health and Addiction
https://doi.org/10.1007/s11469-023-01085-z
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ORIGINAL ARTICLE
Changed Substance Use After Psychedelic Experiences
Among Individuals inCanada
KevinF.Boehnke1,2,3 · DanielJ.Kruger1,4· PhilippeLucas5
Accepted: 16 May 2023
© The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2023
Abstract
We conducted a cross-sectional online survey of adults (n = 1639; 56.3% women) self-report-
ing past or current psychedelic use. We investigated whether psychedelic use was associated
with self-reported changes in the use of other substances. Participants reported substantial
changes, with 43.8% (n = 651/1488) decreasing or ceasing alcohol use, 42.5% (n = 272/640)
ceasing or decreasing antidepressant use, and 42.4% (n = 200/471) decreasing or ceasing
cocaine use. The highest rates of increased use were for cannabis (10.9%; n = 151/1383) and
tobacco products (9.3%; n = 60/646). The most common reasons for substance use reduc-
tions were feeling more connected with self (73%; n = 632), nature (55%; n = 476), and oth-
ers (54.6%; n = 473), as well as feeling less anxious or depressed (59.4%; n = 514). Factors
associated with reduction in any substance use included motivation to treat a medical condi-
tion, number of psychedelics used, younger age, and using both microdoses and macrodoses.
This real-world evidence should be rigorously investigated in future studies.
Keywords Psychedelics· Survey· Addiction· Substance use disorder· Canada·
Substitution
Classic psychedelics include substances such as psilocybin, lysergic acid diethylamide
(LSD), and ayahuasca, and non-classical psychedelics include 3,4-Methylenedioxymeth-
amphetamine (MDMA) and ketamine. (Nichols etal., 2023) Although psychedelics have a
long history of use in numerous cultural, religious, and spiritual contexts, legal restrictions
have limited clinical research involving psychedelics since the 1970s (M. W. Johnson etal.,
2019; Perkins etal., 2021). However, in the past 15 years, clinical interest in psychedelics
for treating various mental health conditions has been rekindled (DiVito & Leger, 2020;
* Kevin F. Boehnke
kboehnke@med.umich.edu
1 Anesthesiology Department, University ofMichigan Medical School, 24 Frank Lloyd Wright
Drive, AnnArbor, MI48106, USA
2 Chronic Pain andFatigue Research Center, University ofMichigan Medical School, AnnArbor, MI, USA
3 Michigan Psychedelic Center, University ofMichigan, AnnArbor, MI, USA
4 Population Studies Center, University ofMichigan, AnnArbor, MI, USA
5 SABI Mind, Calgary, AB, Canada

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Perkins etal., 2021). Psychedelics are now being investigated as potential treatments for
numerous psychiatric disorders and other conditions, with recent clinical trials for major
depression disorder and treatment resistant depression showing substantial improvements
in depressive symptoms after 1–2 doses of psilocybin in concert with psychotherapy
(Carhart-Harris etal., 2021; Davis etal., 2021; Goodwin etal., 2022).
Some studies suggest that psychedelics have potential for treating substance use disorders
(SUD), such as tobacco and alcohol use disorders. For example, a meta-analysis of randomized
controlled trials (n = 8) found a beneficial effect of LSD on alcohol misuse (Fuentes etal.,
2019). A recent trial of among people with alcohol use disorder demonstrated that the percent-
age of heavy drinking days and mean daily alcohol consumption decreased following psilocy-
bin-assisted therapy, compared to diphenhydramine (Bogenschutz etal., 2022). Another small,
open-label trial administered moderate and high doses of psilocybin to healthy nicotine-depend-
ent smokers and found the observed smoking cessation rate was substantially higher than for
traditional therapies, with an 80% abstinence rate after 6 months follow-up (M. W. Johnson
et al., 2014; M. W. Johnson et al., 2017). Lastly, a small observational study of ayahuasca-
assisted treatment among 12 individuals in Canada led to self-reported declines in cocaine,
tobacco, and alcohol use persisting 6 months following treatment (Thomas etal., 2013).
Concurrent with revitalized clinical research, the State of Oregon and numerous
municipalities in the United States (US) have decriminalized various classic psyche-
delics, (Boehnke etal., 2022) and both psilocybin and MDMA have been granted status
as breakthrough therapies by the US Food and Drug Administration. Similarly, in Janu-
ary 2022, Health Canada added psychedelics to the list of treatments available under the
Special Access Program, allowing physicians to request access to psychedelics for patients
with serious health conditions and limited conventional treatment options (Champagne &
Ramadan, 2022). Although the consequences of these changed policies on public health
remain to be fully elucidated, several surveys of people in the US using psychedelics
Fig. 1 Self-reported changes in substance use following from psychedelic use. Note: “n” represents the
number of participants that identified current or past use of the substance listed; proportions represent
self-reported changes in use for these participants. The most participants reported no changes, followed by
decreased or stopped use, followed by increased or initiated use of substances

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naturalistically (typically without the structure or therapeutic support used in clinical tri-
als) report decreased use of several substances, including tobacco, alcohol, and opioids
(Garcia-Romeu etal., 2019a; Garcia-Romeu etal., 2019b). In a recent study of 1435 peo-
ple who had used psychedelics in the past 5 years in the US, we showed many reported
decreases in alcohol (37.2%), tobacco/nicotine (18.3%), and opioid prescription use (7.2%)
after using psychedelics (Glynos etal., 2022). Taken together, these findings suggest that
people are using psychedelics for medical purposes outside of conventional medical path-
ways and changing their use of other substances as a result, a finding that mirrors trends
in the medical cannabis use landscape (Boehnke etal., 2019; Boehnke etal., 2021; Lucas
etal., 2016; Lucas etal., 2021).
In the current study, we investigated patterns of naturalistic psychedelic use and self-
reported changes in substance use among a large convenience sample of adults with past or
current psychedelic use in Canada, where little is known about individual patterns of real-
world psychedelic use. We hypothesized that people would report reductions in substance
use following naturalistic psychedelic use, most commonly for alcohol and tobacco. We
then explored demographic and use characteristics associated with self-reported decreases
in substance use.
Methods
The Canadian Psychedelic Survey is a large, convenience sample designed to gather
detailed ecological data on the adult use of 11 common substances with psychedelic
or hallucinogenic effects. These substances included so-called “classic” psychedelics
(ayahuasca, N, N-dimethyltryptamine (DMT) or 5-methoxy-N,N-dimethyltryptamine
(5-MeO-DMT), LSD or acid iboga or ibogaine, 2C-B (2-(4-bromo-2,5-dimethoxyphenyl)
ethanamine), mescaline, and psilocybin) as well as compounds that have dissociative or
hallucinogenic effects that may interact directly or indirectly with the serotonergic system
(3,4-methylenedioxymethamphetamine or 3,4-methylenedioxyamphetamine (MDMA or
MDA), nitrous oxide, and salvia divinorum) (Joca etal., 2019; Nagele etal., 2018; Nichols
etal., 2023; Varias etal., 2020). This survey was developed in collaboration with academ-
ics from numerous universities. The survey was ethics reviewed by Advarra (protocol #
Pro00059863) and co-sponsored by SABI Mind, the Multidisciplinary Association of Psy-
chedelic Studies Public Benefits Corp. (MAPS PBC) and Psygen Labs Inc.
Sample
To take part in the study, participants had to be 19 years old or older, self-report past or
current use of psychedelics, have the capacity to consent for themselves, and were able
to read, write, and speak English. Informed consent was gathered online, and all data was
collected anonymously. However, participants could provide an email address to be entered
into a draw to win one of 3 × $500 Amazon gift cards as compensation for taking the
time to participate in the study, after which all email addresses gathered for the draw were
immediately destroyed.
Data collection took place Jan. 14–28, 2022. Distribution was via NGOs like MAPS
Canada, the Psychedelic Association of Canada, and the Canadian Drug Policy Coali-
tion, as well as social media, and respondents completed the survey online on REDCap, a
HIPAA and PIPEDA compliant electronic data capture system.

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Measures
This survey included multiple choice, Likert Scales, and textual response questions. Patient
characteristic items gathered information on age, province of residence, self-identified
racial background, gender, relationship and employment status, education, and annual
income. The entire survey was 655 questions assessing patterns of use and numerous
domains of psychedelic use. For the current manuscript, we focused on questions regarding
changes in medications, illicit drugs, and licit drugs (e.g., tobacco and alcohol) following
naturalistic psychedelic use.
Changes inSubstance Use
We asked participants if their use of any substances including alcohol, antidepressants,
benzodiazepines, cannabis, cocaine/crack, methamphetamine, non-prescription opioids,
prescription opioids, and tobacco/nicotine changed because of their psychedelic use.
Participants could report ceased use, decreased use, no change in use, initiation of use,
increased use, or note that they did not use that substance. Participants who reported a
decrease in substance use of any kind were asked to identify the psychedelic that was par-
ticularly impactful in ceasing or decreasing use of other substances. We then asked par-
ticipants who decreased or ceased use of substances how psychedelics helped them cease
or decrease that use, with options including: Helped reduce cravings/urges, helped reduce
withdrawal, they made me less anxious or depressed, helped me resolve past trauma, made
me feel more connected with nature, made me feel more connected with myself, made
me feel more connected with others, and none of the above. Participants could select all
answers that applied. Finally, we asked these participants how long the decrease in sub-
stance use typically persisted after using psychedelics, with responses options of: Less than
1 week, 1–4 weeks, 5–11 weeks, 12–-26 weeks, > 26 weeks, and no set pattern/depends on
the substance and circumstances.
Data Cleaning
For the analysis, respondents with verified Canadian postal codes were included. Addi-
tional data cleaning steps included: removing an observation where the variable “LSD/
Acid times” was equal to 2009 and identifying duplicates among participants based on the
combination of gender, age, relationship, postal code, education, and income. After remov-
ing these duplicates and including only respondents who answered questions on changed
substance use following use of any psychedelic, there were n = 1639 responses for the final
analysis.
Statistical Analysis
We examined participant demographics by whether their use of other substances changed
following psychedelics use (see Table1). We calculated proportions of participants report-
ing each psychedelic particularly impactful in ceasing or decreasing use of other sub-
stances, endorsing reasons why psychedelics helped them to cease or decrease the use of
other substances, and how long the decrease in substance use typically persisted after using

International Journal of Mental Health and Addiction
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psychedelics (see Table2). Logistic regression examined predictors of the decreased use
of other drugs following use of psychedelics. Candidate predictors included age, gender,
household income, level of education, whether participants identified as White, the number
of different psychedelics used, whether participants only microdosed psychedelics, whether
participants had a medical motivation to use psychedelics, and whether participants had
a recreational motivation to use psychedelics (see Table 3). For gender, we used dummy
variables to compare: (1) female vs. all other genders (male or other gender, inclusive), and
(2) other gender identities vs. male or female.
Results
In our study population of N = 1639 participants, a higher proportion of participants who
decreased use of substances were female, younger, used more psychedelics, and used both
micro and macrodoses of psychedelics than those who did not report decreased use of other
substances. Participants reported substantial changes in use of various substances, with 43.7%
(n = 651/1488) decreasing or ceasing alcohol use, 42.5% (n = 272/640) ceasing or decreas-
ing antidepressant use, and 42.4% (n = 200/471) decreasing or ceasing cocaine use(Fig.1).
Overall, n = 222 (13.5%) reported any increase in substance use or initiation use of any sub-
stance, with n = 184 (11.2%) participants reporting increased use of any substance and n =
74 (4.5%) reporting initiating use of any substance. The highest rates of increased use were
for cannabis (10.9%; n = 151/1383) and tobacco (9.3%; n = 60/646). The highest rate of
initiated use was for amphetamines (3.5%; n = 7/202). Those who reported any drug reduc-
tion were younger, t(1637) = 2.2; p = .027; d = .11, and reported using a greater number of
psychedelic substances, t(1637) = 10.3; p < .001; d = .51 (see Table 1). A higher propor-
tion of men reported reductions in drug use than women, χ2(1) = 5.3; p = .02, and a higher
Table 1 Participant demographics by whether their use of other substances changed following psychedelic
use
Psychedelics indicate the number of psychedelics taken at a regular dose in the past year
* indicates p < .05
** indicates p < .001
a This includes participants who did not change their use as well as those who either increased their use of
an existing substance or initiated use of a new substance
Descriptive Decreased use (n = 866) No decreased usea (n = 773)
Gender**
Women 51.7% (448) 59.6% (461)
Men 40.8% (353) 37.0% (286)
Non-binary 6.0% (52) 2.6% (20)
Other 1.5% (13) 0.9% (6)
Age in years* (M, SD, and range) 37.4, 12.2, 19–79 38.7, 12.9, 19–82
Psychedelics** (M, SD, and range) 4.2, 2.3, 0–12 3.0, 2.1, 0–10
Dosages used**
Microdose only 3.9% (34) 10.0% (75)
Macrodose only 34.8% (298) 53.1% (398)
Both microdose and macrodose 61.3% (525) 36.8% (276)
Missing 1.0% (9) 3.1% (24)

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proportion of those who identified as non-binary reported reductions in drug use than men,
χ2(1) = 7.6; p = .006. A higher proportion of respondents with the motivation to treat a medi-
cal condition with psychedelics reported drug use decreases (72.4%), compared to those who
were not treating a medical condition (41.2%; χ2(1) = 149.8; p < .001).
Most participants (57.7%) reported that psilocybin was particularly impactful in ceas-
ing or decreasing their use of other substances, with LSD or Acid mentioned next most
often (13.0%; see Table2). All other psychedelics were reported by less than 10% of par-
ticipants as particularly impactful in ceasing or decreasing their use of other substances.
Nearly half (47.0%) reported no set pattern in how long decreases in substance use typi-
cally persist after using psychedelics, or that it depends on the substance and circumstances
(see Table 2). About one-quarter (26.9%) reported that the reduction in substance use
lasted a month or less, whereas 14.3% reported that it lasted for more than half a year. The
most common reasons for decreased drug use after use of psychedelics were feeling more
Table 2 Impacts of specific psychedelics on substance use and persistence of effects
n =866 % of Total
Which of the following psychedelics did you find particularly impactful in ceasing or decreasing your use
of other substances?
Psilocybin 500 57.7
LSD/Acid 113 13.0
MDMA/MDA 45 5.2
Ayahuasca 40 4.6
Ketamine 30 3.5
DMT/5-MeO-DMT 13 1.5
Iboga/Ibogaine 5 0.6
Mescaline 4 0.5
2C-B 2 0.2
Nitrous oxide 2 0.2
Salvia divinorum 1 0.1
None of the above 111 12.8
How have psychedelics helped you to cease or decrease the use of other substances?
Made me feel more connected with myself 632 73.0
Made me less anxious or depressed 514 59.4
Made me feel more connected with nature 476 55.0
Made me feel more connected with others 473 54.6
Helped me resolve past trauma 339 39.1
Helped reduce cravings/urges 326 37.6
Helped reduce withdrawal 121 14.0
None of the above 100 11.5
How long does the decrease in substance use typically persist after using psychedelics?
Less than 1 week 62 7.2
1–4 weeks 171 19.7
5–11 weeks 67 7.7
12–26 weeks 35 4.0
> 26 weeks 124 14.3
No set pattern/depends on the substance and circumstances 407 47.0

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connected with self (73.0%; n = 632), nature (55.0%; n = 476), and others (54.6%; n =
473), as well as feeling less anxious or depressed (59.4%; n = 514). Those who had a med-
ical motivation to use psychedelics, who used a greater number of different psychedelics,
were younger in age, and used psychedelics in both microdoses and macrodoses were more
likely to report reduction of other drugs following their use of psychedelics (see Table3).
Discussion
In this large convenience sample of people, we show that 52.8% self-report decreas-
ing their use of non-psychedelic substances as the result of naturalistic psychedelic use.
Consistent with our hypotheses, the substances most frequently reduced included alco-
hol, antidepressants, crack/cocaine, and tobacco products. Reported persistence of this
decreased used ranged from 4 weeks or fewer (26.8%) to > 26 weeks (14.2%), with nearly
half of the study population reporting that there was no pattern in the length of reduc-
tions, or that the pattern depended on the substance used and circumstances of use. Of
note, psilocybin (57%) and LSD (13.3%) rated as the most cited psychedelics leading to
decreasing or ceasing use of other substances, and the most common explanatory rea-
sons noted by participants for reductions in use were feelings of increased connection with
themselves, nature, or others, as well as feeling less anxious or depressed. Factors associ-
ated with decreased use included citing an intention to use psychedelics to treat a medical
condition, the number of psychedelics used, the frequency of psychedelic use in the past
year, and younger age. The finding that those who self-reported decreases in substance
use cited connection to self and others, and nature is consistent with contemporary theo-
ries on the social dimensions of substance use disorder and echoes the results of other
studies of psychedelics in the treatment of SUD (M. W. Johnson etal., 2014; M. W. John-
son etal., 2017).
Table 3 Predictors of ceasing or decreasing substance use following psychedelic use
a Dummy variable used to compare female vs. all other genders (male or other gender, inclusive)
b Dummy variable used to compare other gender identities vs. male or female. Other gender included self-
descriptions such as “non-binary,” “transman,” and “androgynous”
Predictor Univariate predictions Multivariate predictions
Odds ratios (95% CI) p Odds ratios (95% CI) p
Medical motivation 3.74 (3.02–4.65) <. 001 3.38 (2.66 - 4.29) <. 001
Number of psychedelics used 1.24 (1.20–1.29) <. 001 1.21 (1.15–1.28) <. 001
Age 0.99 (0.98–1.00) .027 0.99 (0.98–1.00) .025
Both microdose and macrodose 2.70 (2.27–3.39) <. 001 2.56 (1.10–5.96) .029
Recreational motivation 0.85 (0.68–1.07) .171 0.77 (0.59–1.01) .062
Female gendera0.73 (0.60–0.88) .001 0.81 (0.65–1.01) .067
White 1.22 (0.91–1.63) .185 1.24 (0.90–1.71) .193
Education in years 0.96 (0.92–1.00) .050 0.97 (0.93–1.02) .212
Macrodose only 0.49 (0.41–0.60) < .001 1.43 (0.62–3.31) .407
Other gendera,b 2.02 (0.62–6.58) .244 1.59 (0.40–6.38) .513
Household income 0.94 (0.88–1.00) .043 1.02 (0.95–1.11) .536
Microdose only 0.38 (0.25–0.58) <. 001 0.84 (0.34–2.10) .712

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We also note that while > 50% of participants did not change their other substance use
after taking psychedelics, and a smaller yet still substantial group of participants attributed
increasing or initiating use of other substances due to psychedelic use. The percentages of
participants who reported increased use were similar to those seen in other similar surveys
(Garcia-Romeu etal., 2019a). Given the rapidly changing legal landscape around psych-
edelics, understanding psychedelic use factors associated with negative health outcomes
is critical for protecting public health. A recent study of people using psychedelics rec-
reationally showed that using psychedelics at higher frequency and to cope with negative
affect were associated with psychological distress and negative mental health. Conversely,
taking psychedelics with a group, going into the experience with intentions around self-
expansion, and seeking out integration after the experience were all associated with posi-
tive outcomes (St. Arnaud & Sharpe, 2023).
Social exclusion and isolation have been found to be strongly associated with SUD
(Wesselmann & Parris, 2021), whereas connection to self and others can be both prophy-
lactic of SUD and help support and sustain treatment and recovery (Best etal., 2021; Cle-
ments etal., 2022; Pettersen etal., 2019). Moreover, increased connection to self, others,
nature, and spirit have been found to be a core component and primary outcome of many
psychedelic experiences (Argento etal., 2019; Thomas et al., 2013; Yaden et al., 2017)
and has recently led to the development of the Watts Connectedness Scale in order to more
sensitively measure connectedness to self, others, and the wider world following psyche-
delic experiences. In light of emerging research highlighting the negative health impacts
of loneliness and isolation (Cacioppo & Cacioppo, 2018) and the growing understanding
of the importance of social connectedness to overall physical and psychological well-being
(Pietrabissa & Simpson, 2020), this may ultimately have broader implications for mental
health research (Watts etal., 2022).
These findings provide real-world evidence that psychedelic use may be affecting pat-
terns of other substance use, complementing other survey literature in this area. For exam-
ple, among n = 343 individuals with prior long term (7+ years) self-reported problem-
atic alcohol use, participants reported a large reduction in alcohol consumption after their
psychedelic experience (Garcia-Romeu etal., 2019b). Of these individuals, 90% retrospec-
tively met moderate or severe AUD criteria, compared to 8.2% currently (i.e., post psyche-
delic experience) meeting moderate or severe AUD. Nearly 3/4 of participants had taken
moderate to high doses of psilocybin mushrooms or LSD, and the mean self-reported num-
ber of drinks per week dropped from 25.5 prior to the experience to 4.3 currently. These
findings were mirrored in a study of n = 444 people with prior cannabis, stimulant, or opi-
oid use disorders: 96% of participants retrospectively met criteria for one of these SUDs,
compared to 27% afterwards (Garcia-Romeu etal., 2019a). As in the first study, moderate
to high doses of LSD (43%) and psilocybin-containing mushrooms (29%) were the most
commonly used psychedelics, and n = 331 (> 70%) had greatly reduced or stop using their
primary substance of use after the experience. Participants in both studies reported that the
psychedelic experience was very meaningful and provided useful insights related to their
well-being.
Implications
The substantial number of participants reporting changes in substance use following natu-
ralistic psychedelic use both warrants future research and demonstrates the need for clini-
cal policy that appropriately accounts for increased psychedelic use. To the latter point,

International Journal of Mental Health and Addiction
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the case of cannabis is quite instructive for anticipating issues that may arise in the future
for clinical applications of psychedelics (Boehnke et al., 2022). Indeed, cannabis legali-
zation first progressed through medical policies, typically driven both by compassionate
use arguments and recognition of the negative public health and safety impacts of prohibi-
tion and the failures of the War on Drugs (Earp, Lewis, Hart,, & Reform, 2021). This cul-
minated in Canada legalizing medical cannabis in 2001 and adult-use cannabis 2018, but
much work remains to appropriately integrate cannabis into mainstream medicine or even
have evidence-based conversations between patients and healthcare providers about how
it might impact use of other substances. For example, in a large survey of n = 2,697 peo-
ple using medical cannabis in Canada, 31.3% delayed informing their primary care physi-
cian about substituting cannabis for medications, with 34.8% reporting that their physician
still did not know about their substitution (Holman etal., 2022). We noted a similar trend
in our recent study in which less than 20% of participants using psychedelics naturalisti-
cally disclosed use to their physicians (Glynos etal., 2022). We believe that it is critical to
avoid this same fate with the emerging psychedelic landscape, both because appropriate
therapeutic supports (e.g., preparatory and integration therapy (M. Johnson et al., 2008))
appear to enhance the likelihood of a safe and therapeutic experience thereby maximiz-
ing potential benefits and also because psychedelics may be contraindicated among certain
populations (e.g., people with psychotic conditions), so careful screening can help reduce
potential harms. Furthermore, as demonstrated by cases of abuse by prominent psychedelic
therapists, psychedelics can elicit a state of suggestibility and vulnerability in which peo-
ple should ideally be carefully protected and supported (MacBride, 2021). Although such
abuse is likely more common outside of regulated research space, it still has been known to
occur in clinical trial settings (Lindsay, 2022). As such, we believe there is a critical need
for improved psychedelic-related education among clinicians, more clinical infrastructure
to support patients seeking these services, and finally, a significant shift in medicine to
view psychedelics as a potential medical tool that must be used wisely to maximize benefit
(Boehnke etal., 2022; Moens, 2023). Indeed, with appropriate therapeutic support it seems
plausible that patients would report greater success and be less likely to initiate or increase
use of other substances.
Limitations andStrengths
This study has several limitations. The cross-sectional and self-reported nature of the
survey did not benefit from objective measures of changes in substance use or oppor-
tunities to verify temporality of changes in substance use (which are limited by recall
bias) or to investigate the chemical content of any psychedelic substances reportedly
used. The convenience sampling strategy rends the results subject to selection bias and
leaves us uncertain about the generalizability of results to the larger population of people
using psychedelics in Canada or in North America. However, these limitations are offset
by several strengths. The large sample size provides an in-depth view of how psyche-
delic use may affect the use of other substances, offering useful and actionable informa-
tion for conducting more rigorous studies in the future. Similarly, the questions on how
psychedelics affect one’s relationship with other substances, preferred psychedelic for
changing use of other substances, and the length of changed use offer unique contribu-
tions to the literature that may inform future studies and policy considerations related to
psychedelics.

International Journal of Mental Health and Addiction
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Conclusions
In this large, online survey of Canadians using psychedelics naturalistically, nearly half of
individuals reported substantial decreases in alcohol, tobacco, and other substance use fol-
lowing psychedelic experiences, with 25.9% reporting decreased use for 5 weeks or more.
Participants rated psilocybin as the most impactful psychedelic for ceasing or decreasing use
of other substances and cited reductions in anxiety/depression and increased connectedness
to self, others and nature as the most common explanatory factors for these changes. Over
13% of participants also reported increasing or initiating use of other drugs, highlighting the
public health importance of understanding contextual factors associated with changed sub-
stance use following psychedelic use. Future prospective observational studies and clinical
trials are necessary to validate these findings, identify characteristics associated with psy-
chedelic treatment success, and investigate whether changes in substance use differ among
those who used without support vs. those who had more structured or guided psychedelic
use. Given that naturalistic use typically occurs outside of traditional medical channels, these
findings emphasize the importance of developing appropriate therapeutic infrastructure to
maximize benefit and minimize harm from psychedelics.
Acknowledgements The authors would like to thank all the participants in this study for taking the time to
fill up our survey, and MAPS PBC, SABI Mind, and Psygen for co-sponsoring the Canadian Psychedelic
Survey.
Declarations
Ethical Approval The study was co-sponsored by SABI Mind, the Multidisciplinary Association of Psyche-
delic Studies Public Benefits Corp. (MAPS PBC), and Psygen.
Ethics and Consent The survey was ethics reviewed by Advarra (protocol # Pro00059863).
Consent to Participate Online informed consent was obtained from all the study participants.
Competing Interests Dr. Boehnke has received grant funding from Tryp Therapeutics and Algae Sciences.
He sits on a Data Safety and Monitoring Committee (unpaid) for Vireo Health. Dr. Boehnke’s effort on this
publication was partially supported by the National Institute on Drug Abuse of the National Institutes of
Health under Award Number K01DA049219 (KFB). The content is solely the responsibility of the authors
and does not necessarily represent the official views of the National Institutes of Health. Philippe Lucas PhD
is President of SABI Mind, one of the co-sponsors of this study.
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