Side-effects reporting in clinical trials of psilocybin-assisted psychotherapy (PAP) for psychiatric conditions is inconsistent but improving over time. A systematic review of 24 trials published between 2005 and 2024 found that only six had high-quality side-effects reporting, while nine were low and five were very low. All nine randomized controlled trials showed high risk of bias for side-effects outcomes. There was no evidence of systematic underreporting in published articles compared with trial registers, but variability in reporting hindered comparisons. The authors conclude that existing evidence has a high risk of bias and that future trials should follow best-practice guidelines, and discussions with patients should emphasize current uncertainty about PAP side-effects.
Serotonergic psychedelics and entactogens are being studied as adjuncts in substance-assisted psychotherapy (SAPT) for various disorders. SAPT includes three phases: preparation, administration, and integration, where insights from the psychedelic experience are applied to everyday life. A systematised review of 75 publications found that the effects of different therapeutic approaches for integration sessions on outcomes have not been rigorously investigated. Most available evidence lacks empirical data, limiting conclusions about appropriate frameworks. Current clinical studies mostly draw from the humanistic–experiential tradition. Although integration is considered crucial for safe SAPT, there is insufficient evidence to suggest any therapy type is effective for guiding integration sessions.
The authors argue that existing evidence on adverse effects of psilocybin-assisted psychotherapy is undermined by methodological problems, such as small sample sizes, lack of standardized reporting, and inadequate control conditions. They call for more rigorous research to accurately assess risks before clinical adoption.