Skip to content

Ryan M Brudner

University of Toronto, Toronto, Canada.

4 papers in the library · 109 citations · publishing 2024-2025

Papers

Psilocybin-assisted psychotherapy for treatment resistant depression: A randomized clinical trial evaluating repeated doses of psilocybin.

Med (New York, N.Y.) March 8, 2024 Joshua D Rosenblat, Shakila Meshkat, Zoe Doyle et al. 97 citations

Psilocybin-assisted psychotherapy (PAP) is feasible for patients with complex, treatment-resistant depression, including those with bipolar II disorder and baseline suicidality. In a randomized trial with 30 adults, those receiving immediate PAP showed greater reductions in depression severity (MADRS) compared to a waitlist control, with a large effect size (Hedge's g = 1.07). Adverse events were transient and no serious adverse events occurred. Repeated doses over six months were associated with further improvement. The findings suggest PAP can be safely delivered to this population and warrants further study.

Psilocybin-Assisted Psychotherapy for Treatment-Resistant Depression in Bipolar II Disorder

Psychedelic Medicine November 18, 2024 Shakila Meshkat, Erica Kaczmarek, Zoe Doyle et al. 8 citations

In a small subgroup analysis of four adults with treatment-resistant depression associated with bipolar II disorder, two 25 mg doses of psilocybin combined with psychotherapy were associated with reductions in depressive symptoms. The average depression score on the Montgomery–Åsberg Depression Rating Scale dropped from 32.5 at baseline to 20.3 two weeks after the first dose, and to 19 two weeks after the second dose; at six months the average score was 21.3. Mania ratings remained stable, and no mania, hypomania, or psychosis occurred. The authors suggest psilocybin may improve depressive symptoms in bipolar II disorder but call for larger studies to confirm the findings.

Examining mystical experiences as a predictor of psilocybin-assisted psychotherapy for treatment-resistant depression

Journal of Psychopharmacology July 1, 2025 Ryan M Brudner, Erica Kaczmarek, Marc G Blainey et al. 3 citations

In a small sample of 31 individuals with treatment-resistant major depressive disorder or bipolar II disorder, those who reported more intense mystical experiences after their first dose of psilocybin-assisted psychotherapy showed greater reductions in depressive symptoms two weeks later. This link between mystical experiences and antidepressant benefit was not observed after the second or third psilocybin doses. The findings offer preliminary support for the idea that mystical-type experiences play a therapeutic role in psilocybin-assisted psychotherapy, extending prior work to a clinically complex population with treatment-resistant depression.

Comparing Antidepressant Effects of Psilocybin-Assisted Psychotherapy in Individuals That Were Unmedicated at Initial Screening Versus Individuals Discontinuing Medications for Study Participation: Comparaison des effets antidépresseurs de la psychothérapie assistée par la psilocybine (PAP) chez les personnes non médicamentées à la sélection initiale et les personnes ayant arrêté les médicaments pour participer à l’étude

The Canadian Journal of Psychiatry March 25, 2025 Noah Chisamore, Erica S Kaczmarek, Zoe Doyle et al. 1 citation

A single 25 mg dose of psilocybin combined with psychotherapy produced clinically significant reductions in depression, anxiety, and suicidality symptoms over two months in people with treatment-resistant depression. Among 27 participants, those who tapered off antidepressant medications before treatment (n = 18) and those not on antidepressants at screening (n = 9) showed comparable improvements, with no significant differences between groups on clinician-rated depression, self-reported depression, anxiety, or suicidality. The intensity of the psychedelic experience was also similar. These results suggest that tapering antidepressants before psilocybin-assisted psychotherapy may not diminish therapeutic benefits, though further research is needed.