A single 25 mg dose of synthetic psilocybin combined with psychotherapy produced rapid and sustained reductions in depression symptoms in people with bipolar II disorder who had not responded to at least two prior treatments. Fifteen participants completed the trial; depression scores on the Montgomery-Åsberg Depression Rating Scale dropped by an average of 24 points three weeks after dosing, and 12 of 15 met both response and remission criteria by the 12-week endpoint. Mania and suicide risk scores did not increase. The open-label design limits certainty, but the results suggest psilocybin may be safe and effective for bipolar II depression.
In an open-label study, psilocybin appears effective and safe for people with severe treatment-resistant depression, supporting further research into psychedelics for this group, including how post-traumatic stress disorder may affect outcomes.
Patients with treatment-resistant unipolar major depressive disorder who qualified for the RECOVER trial—the largest randomized sham-controlled study of vagus nerve stimulation for a psychiatric condition—had severe disability, a median of 11.0 prior failed antidepressant treatments, and high rates of suicidality (77% with suicidal ideation, 40% with previous suicide attempts). Seventy-one percent had received at least one prior interventional psychiatric treatment (electroconvulsive therapy, transcranial magnetic stimulation, or esketamine). Compared to those without such history, recipients of interventional treatments were younger, more severely depressed, had greater suicidal ideation, earlier onset of depression, and more failed medication trials.
A single 25-mg dose of a synthetic psilocybin formulation, combined with psychological support, rapidly and durably reduced chronic suicidal ideation and depressive symptoms in 20 adults with major depressive disorder who had not responded to at least two prior antidepressant treatments. Suicidal ideation scores dropped significantly by week 1, remained reduced at week 3 (the primary endpoint), and were still lower at week 12, when 70% of participants had minimal or no suicidal ideation. Depressive symptoms also improved substantially. No serious adverse events occurred. The findings are preliminary and require confirmation in larger randomized trials.