Are psychedelics anti-inflammatory? A systematic review and meta-analysis of studies examining the immunomodulatory effects of serotonergic psychedelics
Psychedelics may reduce inflammation under certain conditions, particularly in preclinical models with elevated baseline inflammation
This systematic review and meta-analysis examined whether serotonergic psychedelics, such as psilocybin, LSD and DMT, have anti-inflammatory effects. Across 61 studies, the researchers found that most cell-based studies (79%) and animal studies (83%) reported anti-inflammatory effects. The meta-analysis of mouse studies found a substantial reduction in pro-inflammatory cytokines in animals with experimentally induced inflammation, whereas no significant reduction was observed in healthy mice. This suggests that psychedelics may have a greater effect on regulating an already activated inflammatory response than on reducing inflammation under normal conditions.
However, the evidence in humans remains limited and inconsistent. Of the 10 human trials included, only three reported anti-inflammatory effects, and the available clinical evidence was insufficient to draw firm conclusions. Although these findings provide a promising basis for further research into psychedelics and inflammatory conditions, changes in inflammatory markers do not necessarily translate into improved health outcomes. Overall, the study suggests that psychedelics may have immunomodulatory properties, but further high-quality human trials are needed before they can be considered effective or safe treatments for inflammation-related diseases.
Abstract
Serotonergic psychedelics are promising treatments for neuropsychiatric disorders, and their immunomodulatory effects may contribute to their clinical efficacy. However, we lack a systematic review and meta-analysis of these effects across in vitro, in vivo non-human, and human studies. We systematically searched PubMed, EMBASE, Web of Science, PsycINFO, LILACS and ClinicalTrials.gov for all studies, published from database inception through February 9th, 2026, examining changes in immune markers after serotonergic psychedelic exposure, and meta-analyzed eligible studies. Of 9,195 studies screened, 61 studies met eligibility criteria for systematic review including 24 in vitro studies, 30 non-human in vivo studies, and seven human studies including data from 10 separate human trials. Results of the systematic review indicated that most in vitro (19/24) and non-human in vivo (25/30) studies reported anti-inflammatory effects of psychedelics. Human results were mixed with anti-inflammatory effects observed in 3/10 trials. Results of the meta-analysis of 18 eligible in vivo murine studies showed a significant decrease in proinflammatory cytokines in inflammatory models (standardized mean difference (SMD = -1.23, 95% CI [-1.54, −0.92]), but no significant effects in healthy murines (SMD = -0.06, 95% CI [-0.54, 0.43]), following treatment with a serotonergic psychedelic. Four human studies were eligible for meta-analysis; however, the small number of studies resulted in imprecise estimates and limited interpretability. Thus, while serotonergic psychedelics reduce proinflammatory cytokines in preclinical models of increased baseline inflammation, limited human evidence precludes conclusions about their translational potential.
Lerche, A.S., Kelley, D.P., Benros, M.E., Billac, G., Bradley, E.R., Heifets, B., Woolley, J., Nishimi, K. and O’Donovan, A. (2026) ‘Are psychedelics anti-inflammatory? A systematic review and meta-analysis of studies examining the immunomodulatory effects of serotonergic psychedelics’, Brain, Behavior, and Immunity, 139, article 107033.Read Paper
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