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Who believes psychedelic-assisted therapies work? Risky cannabis use and other factors are associated with positive treatment-outcome expectancies

Dan Petrovitch, Sean M. Mitchell, Jason van Allen, Andrew K. Littlefield

preprint DOI: 10.31234/osf.io/adnpg (opens in new tab)

Study at a glance

AI-extracted from the abstract
Characteristics Observational survey study
Sample size 309
Population Undergraduates (73% female, 81% White, 30% Hispanic, 22% psychedelic-experienced; mean age 19.95 years)
Topics Cannabis Psychedelic-assisted therapy
Key findings Riskier cannabis use was significantly associated with more positive treatment-outcome expectancies for psilocybin- or LSD-assisted therapy, whereas riskier drinking and other drug use were not significant predictors. Prior engagement with psychedelic-related media and exposure to others' psychedelic experiences also predicted expectancies. The authors suggest clinical trials of psychedelic-assisted interventions for cannabis use disorder may be particularly vulnerable to expectancy-related confounds.

Abstract

Introduction: Treatment-outcome expectancies are an individual’s beliefs about how a medical or psychological intervention will affect them and others. These response expectancies represent serious potential confounds to clinical trials of psychedelic-assisted therapies for a variety of conditions because of difficulties associated with blinding psychedelic trials. On the other hand, expectancies also represent opportunities for practitioners to promote desired clinical outcomes. Therefore, a stronger understanding of factors associated with positive treatment-outcome expectancies for psychedelics could be useful to both scientists and clinicians.

Method: The present study examined treatment-outcome expectancies for psychedelic-assisted therapies with psilocybin or lysergic acid diethylamide (LSD) among undergraduates (73% female, 81% White, 30% Hispanic, and 22% psychedelic-experienced; Mage = 19.95 years, median = 19.0, SD = 3.14). A generalized linear mixed model (GLMM) was used to test the hypothesis that riskier alcohol, cannabis, and other substance use would be associated with more positive treatment-outcome expectancies.

Results: Consistent with our hypothesis, riskier cannabis use was significantly associated with more positive expectancies. However, neither riskier drinking nor other drug use were significant predictors. Prior engagement with psychedelic-related media and exposure to other peoples’ psychedelic experiences also predicted treatment-outcome expectancies.

Conclusion: Individuals with riskier cannabis use may hold stronger beliefs in the transdiagnostic effectiveness of psychedelic-assisted therapies. This suggests that clinical trials of psychedelic-assisted interventions for cannabis use disorder may be particularly vulnerable to expectancy-related confounds. Psychedelic-therapy practitioners treating patients with risky cannabis use may consider patients’ beliefs in the effectiveness of psychedelics when discussing treatment options and delivering psychedelic interventions.