A single dose of psilocybin combined with psychotherapy produced significant improvements in emotional and existential distress in patients with cancer that lasted more than 4 years, according to a study published online in the Journal of Psychopharmacology.
The finding stems from a follow-up investigation of a 2016 study in the same journal that linked psilocybin, a compound found in psychedelic mushrooms, with substantial improvements in anxiety and depression. That study involved 29 patients with cancer, each of whom received a single dose of either psilocybin or active placebo along with 9 sessions of psychotherapy over 7 weeks. Afterward, participants swapped treatments.
In addition to immediate improvements in anxiety and depression, the original study linked the single administration of psilocybin with enduring antianxiety and antidepressant effects 6.5 months later. The newest study, which involved a subset of participants from the original trial, analyzed assessment data taken 3 years and 4.5 years after the single-dose psilocybin administration and identified sustained drops in anxiety, depression, hopelessness, demoralization, and death anxiety at both follow-up points.
At 4.5 years, between 60% and 80% of participants continued to have significant antidepressant or anxiolytic responses to the original treatment, researchers reported. Between 71% and 100% of participants said the psilocybin-assisted therapy experience fueled positive life changes and considered it the one of the most meaningful and spiritually significant events of their lives.
The follow-up study is the longest-spanning investigation into the effects of psilocybin on cancer-related distress. Researchers plan to expand their research with larger trials of patients with cancer-related psychiatric and existential distress.
Agin-Liebes GI, Malone T, Yalch MM, et al. Long-term follow-up of psilocybin-assisted psychotherapy for psychiatric and existential distress in patients with life-threatening cancer. Journal of Psychopharmacology. 2020 January 9;[Epub ahead of print].