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Ryan M. Brudner

University of Toronto

2 papers in the library · publishing 2025-2026

Papers

Examining the effects of psilocybin-assisted psychotherapy on anhedonia in treatment-resistant depression

Journal of Affective Disorders February 12, 2026 Erica Kaczmarek, Nelson Rodriguez, Noah Chisamore et al.

Anhedonia, a core symptom of depression that often resists standard treatments, may be reduced by psilocybin-assisted psychotherapy (PAP). In a secondary analysis of a randomized, waitlist-controlled trial, 30 adults with treatment-resistant depression (major depressive disorder or bipolar II disorder) received one 25 mg dose of oral psilocybin plus psychotherapy. Anhedonia severity, measured by the Snaith-Hamilton Pleasure Scale, decreased significantly at the 2-week primary endpoint, with clinically meaningful improvements persisting at 3 and 6 months. The analysis adjusted for sex and age. These preliminary results suggest PAP could be a promising intervention for anhedonia in treatment-resistant depression, though larger placebo-controlled trials are needed to confirm the findings and clarify underlying mechanisms.

Cognitive outcomes following psilocybin-assisted therapy in treatment-resistant depression: A post-hoc analysis of a randomized, waitlist-controlled trial

Progress in Neuro-Psychopharmacology and Biological Psychiatry November 22, 2025 Shakila Meshkat, Noah Chisamore, Zoe Doyle et al.

A single dose of psilocybin was linked to small, temporary gains in processing speed and executive function in people with treatment-resistant depression. These cognitive improvements seemed unrelated to mood changes but did not consistently surpass the improvements expected from simply retaking the tests. The findings underscore the need for larger, controlled studies to determine whether psilocybin genuinely enhances cognition or if the observed changes stem from practice effects or mood shifts.