First Human Trial Suggests Psilocybin May Reduce Inflammation in Parkinson's Disease

Researchers at the University of California, San Francisco (UCSF) published the first human data in JAMA Psychiatry on 21 October 2026 suggesting that psilocybin, the active compound in psychedelic mushrooms, may reduce inflammation in people with Parkinson's disease. The pilot study enrolled 12 participants with Parkinson's, a condition characterised by chronic neuroinflammation and mitochondrial dysfunction, and administered two psilocybin sessions over the course of the study. Blood tests measured five signalling molecules involved in inflammation both before and after the sessions. The researchers found meaningful reductions in these inflammatory biomarkers following the psilocybin treatment. Earlier laboratory studies had already shown anti-inflammatory effects in animals, but this was the first trial to record such signals in human patients. The study has significant limitations: there was no control group, all participants knew they were receiving psilocybin, and the sample size was very small. The authors called for larger, randomised controlled trials before drawing clinical conclusions. Nevertheless, the findings were described as an important proof-of-concept suggesting a potential new avenue for treating neurodegenerative diseases where inflammation plays a central role, including Parkinson's and possibly other conditions.