Changed Substance Use After Psychedelic Experiences Among Individuals in Canada

Psychedelics have re-emerged in clinical research as potential treatments for a range of psychiatric conditions, with recent trials reporting marked improvements in depressive symptoms after one or two doses of psilocybin combined with psychotherapy. Earlier studies and meta-analyses have also suggested therapeutic potential for substance use disorders (SUDs), for example reductions in alcohol misuse after LSD or psilocybin-assisted interventions and high smoking cessation rates in small open-label psilocybin studies. Concurrently, policy changes in parts of North America and new regulatory pathways (for example Health Canada’s Special Access Program) have increased access to psychedelics outside traditional research settings, raising questions about population-level effects on other substance use. Boehnke and colleagues set out to characterise patterns of naturalistic psychedelic use in Canada and to examine self-reported changes in the use of other substances following psychedelic experiences. They hypothesised that participants would most commonly report reductions in alcohol and tobacco use, and they also explored demographic and use-related factors associated with self-reported decreases in other drug or medication use.

The study used a cross-sectional, online convenience survey called the Canadian Psychedelic Survey, developed with academic collaborators and ethics-reviewed (Advarra). Data were collected anonymously via REDCap between 14–28 January 2022. Recruitment targeted adults (≥19 years) who self‑reported past or current use of psychedelics; respondents needed capacity to consent and English literacy. Distribution channels included NGOs involved in psychedelic research and public-facing social media. Participants could optionally supply an email for a prize draw; emails were destroyed after selection. The instrument comprised 655 items covering demographics and patterns of use across 11 psychedelic or hallucinogenic substances (classic psychedelics such as psilocybin, LSD, ayahuasca, DMT/5‑MeO‑DMT, mescaline, iboga/ibogaine, 2C‑B; and non‑classic compounds such as MDMA/MDA, nitrous oxide, and salvia divinorum). For this analysis the authors focused on questions about changes in use of medications, illicit drugs, and licit substances (alcohol, tobacco) that participants attributed to psychedelic use. Participants indicated for each listed substance whether their use had ceased, decreased, stayed the same, been initiated, or increased following psychedelic use, or whether they did not use the substance. Those reporting decreased or ceased use named which psychedelic they felt was particularly impactful, selected one or more reasons for the reduction from a defined list (for example reduced cravings, less anxiety/depression, greater connectedness to self/others/nature, resolving trauma), and indicated how long the decrease typically persisted (time categories from <1 week to >26 weeks, or “no set pattern”). Data cleaning retained responses with verified Canadian postal codes, removed duplicates and outliers, and limited the analytic sample to respondents who answered the substance change questions, yielding n = 1639. Analyses described participant demographics by whether they reported changes in other substance use, tabulated proportions for psychedelics named as impactful, reasons for reductions, and persistence durations. Logistic regression models tested predictors of decreased use, with candidate predictors including age, gender (dummy variables comparing female vs others and other genders vs male/female), household income, education, White identity, number of different psychedelics used, exclusive microdosing, and medical or recreational motivation for psychedelic use.

The final analytic sample comprised N = 1639 respondents. A substantial fraction of participants reported reductions in their use of other substances following naturalistic psychedelic experiences: 43.7% (n = 651/1488) reported decreasing or ceasing alcohol use, 42.5% (n = 272/640) reported ceasing or decreasing antidepressant use, and 42.4% (n = 200/471) reported decreasing or ceasing cocaine use. Overall, 222 participants (13.5%) reported either an increase in use or initiation of another substance; specifically, 184 (11.2%) reported increased use and 74 (4.5%) reported initiation of any substance. The largest rates of increased use were for cannabis (10.9%; n = 151/1383) and tobacco (9.3%; n = 60/646), while initiation was highest for amphetamines (3.5%; n = 7/202). Comparisons between participants who did versus did not report reductions showed that those reporting decreases were younger (t(1637) = 2.2; p = .027; d = .11) and had used a greater number of different psychedelics (t(1637) = 10.3; p < .001; d = .51). Gender comparisons indicated a higher proportion of men than women reported reductions (χ2(1) = 5.3; p = .02), and a higher proportion of respondents identifying as non‑binary reported reductions than men (χ2(1) = 7.6; p = .006). Intention to treat a medical condition was strongly associated with reductions: 72.4% of those using psychedelics with medical motivation reported decreases in other drug use compared with 41.2% of those without that motivation (χ2(1) = 149.8; p < .001). Psilocybin was the psychedelic most commonly named as particularly impactful in reducing or ceasing other substance use (reported by 57.7% of those who decreased use), followed by LSD/“acid” (≈13%). Regarding duration, 47.0% reported no set pattern or that persistence depended on substance and circumstances, 26.9% indicated reductions typically lasted a month or less, and 14.3% reported reductions lasting more than half a year. When asked why psychedelics helped reduce use, the most frequently endorsed reasons were feeling more connected with oneself (73.0%; n = 632), feeling less anxious or depressed (59.4%; n = 514), feeling more connected with nature (55.0%; n = 476), and feeling more connected with others (54.6%; n = 473). In multivariable analyses, predictors associated with reporting reductions in other substance use included citing medical motivation for psychedelic use, having used a greater number of different psychedelics, younger age, and using both microdoses and macrodoses rather than microdosing only.

Boehnke and colleagues interpret their findings as real‑world evidence that naturalistic psychedelic use is commonly associated with self‑reported reductions in non‑psychedelic substance use in this convenience sample: slightly over half of participants reported decreasing their use of at least one other substance following a psychedelic experience. Alcohol, antidepressants, cocaine/crack, and tobacco products were among the substances most frequently reported as reduced. The authors highlight that reported persistence of reductions varied widely across individuals, with many indicating no consistent pattern and others reporting short‑term or long‑term decreases. The investigators situate these observations alongside prior survey and trial work suggesting that psychedelic experiences can be followed by meaningful reductions in problematic substance use, and they note that psilocybin and LSD were most commonly cited as impactful. Participants most often attributed reductions to increased connectedness (to self, others, nature) and reductions in anxiety or depression; the authors link this pattern to emerging theories emphasising social and existential dimensions of recovery from SUD and to recent efforts to measure connectedness after psychedelic experiences (for example the Watts Connectedness Scale). The discussion also addresses potential harms: a minority of participants reported increased or newly initiated use of other substances, echoing prior surveys and underscoring the public health importance of understanding contextual factors that predict adverse outcomes. The authors argue for clinician education, better therapeutic infrastructure (preparation, integration, screening) and regulatory safeguards to reduce risks such as contraindicated use in vulnerable populations and abuse by providers. Limitations acknowledged by the authors include the cross‑sectional, self‑reported design without objective verification of substance use or psychedelic content, susceptibility to recall and selection bias from convenience sampling, and limited generalisability. Strengths mentioned are the large sample size and detailed questions about which psychedelics were perceived as impactful, reasons for change, and duration of effects, which the authors contend can inform prospective research and policy considerations. They recommend prospective observational studies and clinical trials to validate these associations and to compare outcomes between unsupervised naturalistic use and structured, supported psychedelic treatment.

In their concluding remarks the authors state that nearly half of respondents in this large online Canadian sample reported meaningful decreases in alcohol, tobacco, and other substance use following naturalistic psychedelic experiences, with psilocybin most frequently named as impactful and reductions commonly attributed to decreased anxiety/depression and greater connectedness. They emphasise that over 13% also reported increased or initiated use of other substances, and they call for prospective studies and clinical trials to confirm these findings and for development of therapeutic infrastructure and clinician education to maximise benefits and minimise harms as psychedelics become more accessible.