Psilocybin therapy shows promise as a new treatment for depression and other mental health disorders. The chapter reviews recent data on its safety and efficacy, describes how the therapy is delivered and its subjective effects, and outlines current understanding of psilocybin's pharmacology and neurobiological effects. Other psychedelic substances with therapeutic potential are also briefly discussed.
A single 25-mg dose of psilocybin with psychological support was associated with sustained improvements in anxiety, quality of life, functioning, and PTSD symptoms in 15 veterans with treatment-resistant depression. Anxiety scores dropped 59% from baseline at three weeks and remained lower through 12 months. Quality of life increased 24% and functional impairment decreased 46% at three weeks, though these effects were no longer statistically significant after accounting for concurrent improvements in depression. PTSD symptom reductions were observed at all timepoints. Acute subjective experiences did not correlate with treatment response. The study is limited by its small sample and open-label design.