Psychedelics: Medical risks are often minimal, and that many – albeit not all – of the persistent negative perceptions of psychological risks are unsupported by the currently available scientific evidence

Adverse effects of psychedelics: From anecdotes and misinformation to systematic science. Anne K Schlag et al. Journal of Psychopharmacology, February 2, 2022. https://doi.org/10.1177/02698811211069100

Abstract

Background: Despite an increasing body of research highlighting their efficacy to treat a broad range of medical conditions, psychedelic drugs remain a controversial issue among the public and politicians, tainted by previous stigmatisation and perceptions of risk and danger.

Objective: This narrative review examines the evidence for potential harms of the classic psychedelics by separating anecdotes and misinformation from systematic research.

Methods: Taking a high-level perspective, we address both psychological and psychiatric risks, such as abuse liability and potential for dependence, as well as medical harms, including toxicity and overdose. We explore the evidence base for these adverse effects to elucidate which of these harms are based largely on anecdotes versus those that stand up to current scientific scrutiny.

Results: Our review shows that medical risks are often minimal, and that many – albeit not all – of the persistent negative perceptions of psychological risks are unsupported by the currently available scientific evidence, with the majority of reported adverse effects not being observed in a regulated and/or medical context.

Conclusions: This highlights the importance for clinicians and therapists to keep to the highest safety and ethical standards. It is imperative not to be overzealous and to ensure balanced media reporting to avoid future controversies, so that much needed research can continue.

Keywords: Psilocybin, dimethyltryptamine, ayahuasca, mescaline, d-lysergic acid diethylamide, abuse liability/dependence, hallucinogen persistent perception disorder, toxicity, hypertension

Conclusion

Some of the perceived harms of psychedelics – for example, that they lead to addiction and are neurotoxic – are largely refuted by research of the past decades. Other risks, such as the risks of psychotic episodes or overdose, are rare and only reported in individual cases, but these risks still need to be minimised by careful patient selection and preparation. The past decade of research and clinical experience has increasingly demonstrated how psychedelics can be used safely under medical supervision, and safe use guidelines are progressively well defined (e.g. Griffiths et al., 2006).

Regulatory and legal hurdles of getting psychedelic medicines proven as mainstream medicines are still substantial, so overcoming historic misperceptions is vital. The past decade has seen an increasing focus on research on the therapeutic applications of psychedelics – a direct benefit for the public, which is positively represented in current media (Aday et al., 2019). A recent YouGov study (2017) indicates that public perceptions in the United States becoming more positive, with the majority (63%) being open to medical treatment with psychedelics if faced with a pertinent medical condition, and a UK YouGov survey (2021) corroborates these results.

These changes in public interest are in line with the recent regulatory changes in the United States and Canada. Collectively, these changes in public perception and regulation suggest that the stigma surrounding psychedelics may be beginning to dissipate, and that society is moving away from previous negative narratives to a more scientific, evidence-based approach to risks and benefits of psychedelics as medicine.