A long-term follow-up of a placebo-controlled, randomized, crossover clinical trial found that one or two doses of psilocybin (0.3 mg/kg) combined with psychotherapy produced durable reductions in anxiety and depression in patients with life-threatening cancer. At an average of 3.2 and 4.5 years after dosing, 60–80% of patients continued to show clinically significant improvements in anxiety and depression, as well as sustained benefits in existential distress, quality of life, and attitudes toward death. The psilocybin-induced mystical experience appeared linked to the therapeutic effect. No medications are currently approved for existential distress, and the authors call for larger studies to replicate these findings.
Psilocybin, the active compound in psychedelic mushrooms, can produce substantial and enduring decreases in depressed mood and anxiety in cancer patients when administered in a psychologically supportive setting. In a double-blind phase II study of 51 patients with life-threatening cancer, a single high dose (22 or 30 mg/70 kg) followed by a low dose (1 or 3 mg/70 kg) yielded clinically significant responses. At 6 months, the rate of clinical response for clinician-rated depression was 78%, and for anxiety was 83%. Patients also reported increases in quality of life and decreases in death anxiety. No serious adverse events were noted in a phase I pharmacokinetic study with 12 healthy adults at doses up to 0.6 mg/kg.