Introduction
TRD, treatment-resistant depression, depressive disorder, treatment-resistant, MDD, cancer-related depression
Psilocybin has demonstrated antidepressant properties in preclinical models and small trials of participants with cancer-related depression, major depressive disorder (MDD), and treatment-resistant depression (TRD) [Reports from surveys suggest that the acute subjective psychedelic effects of psilocybin, and of another serotonergic drug, lysergic acid diethylamide (LSD), are diminished by use of antidepressant drugs in the weeks or months prior [In contrast, a recent double-blind randomized controlled trial in healthy participants found that administration of an SSRI for two weeks did not significantly alter the acute subjective effects of 25 mg of psilocybin [This exploratory phase II clinical trial used an open-label, fixed-dose design to investigate the safety and efficacy of a synthetic form of psilocybin with psychological support, adjunct to an SSRI, in participants experiencing a treatment-resistant episode of MDD.