Psilocybin Reduces Inflammation in Parkinson's Patients, First Human Data Shows

Researchers at the University of California, San Francisco, have published some of the first human data suggesting that psilocybin can lower inflammation in patients with Parkinson's disease, with findings appearing in JAMA Psychiatry. The pilot trial enrolled 12 Parkinson's patients who received two supervised psilocybin sessions. Blood tests measuring five distinct inflammation-signalling molecules were taken before and after both sessions. Results showed significantly reduced levels of all five inflammatory markers following treatment, compared to baseline readings, and those reductions persisted one month after the final dose. The team also tracked a blood marker of mitochondrial stress, finding substantial improvements immediately after psilocybin was given, though not at the longer-term follow-up. The findings align with earlier laboratory studies showing that psychedelics bind to serotonin receptors on immune cells and may dampen inflammatory responses. The UCSF team acknowledged major limitations: the trial had no control group, participants knew they were receiving psilocybin, and the sample of 12 was very small. The results must therefore be considered preliminary. However, the study is among the first to demonstrate the anti-inflammatory effect in living humans rather than cell or animal models, and it adds to a growing body of evidence that psychedelics may have therapeutic relevance beyond psychiatry — particularly for neurodegenerative diseases where chronic inflammation plays a key role.