Real-world effectiveness and safety of psychedelic-assisted psychotherapy: Outcomes from a large-scale compassionate use cohort in Switzerland.

Abstract

Classic serotonergic psychedelics such as LSD and psilocybin show promising antidepressant effects in controlled trials, but real-world data from routine clinical care remain limited. This study retrospectively analysed routine data from adults with treatment-resistant depressive and/or anxiety disorders who received a first standardized Psychedelic-assisted Psychotherapy (PAP) cycle with 100 µg LSD or 25 mg psilocybin at a Swiss university hospital (May 2024-October 2025). Self-reported depression (BDI) and trait anxiety (STAI-T) were assessed at screening, one month before treatment, and 1-3 months post-treatment. In a subset of participants, cognitive emotion regulation (CERQ) was assessed pre- and post-treatment. Subjective drug effects and adverse events were recorded on the treatment day. The sample consisted of 115 patients (56.5 % female; Mean age = 47.5 years). Depressive and anxiety symptoms significantly decreased over time (BDI: F(2178) = 63.50, p < 0.001, partial η² = 0.42; STAI-T: F(1.74,145.9) = 16.97, p < 0.001, partial η² = 0.17), with no main effect of substance. CERQ analyses indicated reduced self-blame, rumination and catastrophizing, and increased positive refocusing and reappraisal. Perceived intensity followed distinct temporal profiles for LSD and psilocybin, but comparable subjective drug effects and clinical outcomes. Adverse events were mostly mild and transient, with no serious complications or treatment discontinuations. In this compassionate-use real-world cohort, a first fully-active dose PAP session with LSD or psilocybin was well tolerated and associated with significant improvements in depressive and anxiety symptoms. These findings support the feasibility and effectiveness of PAP in specialised routine care.

In the evidence

This study is part of the evidence base for 3 syntheses in the library. Here is how each one recorded it.

• State of the evidence: LSD and psychedelic-assisted therapy ↑Supports

  A single fully-active dose session of LSD- or psilocybin-assisted psychotherapy was associated with significant reductions in depressive and anxiety symptoms, with mostly mild transient adverse events.

  Synthesized October 22, 2026

• State of the evidence: LSD for anxiety ↑Supports

  A single fully-active dose session of LSD- or psilocybin-assisted psychotherapy was associated with significant reductions in trait anxiety and depression, with mostly mild transient adverse events.

  Synthesized October 22, 2026

• State of the evidence: LSD for depression ↑Supports

  A single fully-active dose session of LSD or psilocybin-assisted psychotherapy was associated with significant reductions in depressive symptoms, with no main effect of substance.

  Synthesized October 22, 2026

Comparable studies

Other observational and cohort studies on LSD and psychedelic-assisted therapy, most cited first.