A small nonrandomized trial has linked psilocybin therapy to reduced markers of systemic inflammation in people with Parkinson's disease and mood dysfunction. The study, published as a research letter in JAMA Psychiatry, tracked 12 patients aged 40 to 75 who received 10 mg and later 25 mg doses of synthetic psilocybin about two weeks apart. Plasma samples from nine participants showed that a proinflammatory index—built from interleukins, tumor necrosis factor alpha, interferon gamma, and C-reactive protein—dropped significantly one day after each dose and remained lower 30 days after the 25 mg dose. One component, IL-6, was significantly lower only after the first dose, while anti-inflammatory IL-10 rose only after the 10 mg dose.
Mitochondrial stress markers told a different story. Growth differentiation factor 15 (GDF-15) decreased significantly one day after each psilocybin administration, but not at the 30-day follow-up. Fibroblast growth factor 21 (FGF-21) trended higher after each dose but not significantly. The authors, led by Ellen Bradley of UCSF, said this is the first report of such marker changes after psychedelic treatment in any neurodegenerative disease. They noted the results support their parent trial, which linked psilocybin to reduced depression, anxiety, and motor symptoms in this population.
Outside experts caution that the open-label design and small sample limit the conclusions. Albert Garcia-Romeu of Johns Hopkins, who studies psilocybin in Alzheimer's disease, said the data suggest psychedelics may produce biological effects beyond psychiatric conditions, but confirmation is needed. The UCSF team already plans a randomized controlled trial in Parkinson's patients with more detailed analyses of inflammation and mitochondrial stress. For now, the findings raise questions about whether these biomarker shifts are consistent and whether they drive any clinical improvement. No direct mechanism or causal link has been established. [Note: Only one source was provided, so no cross-source agreement or disagreement could be assessed.]