Neuroscience: Your brain on psychedelics (Nature Medicine)

Insights into how the human brain reacts to different types of psychedelic drugs are reported in a neuroimaging study in Nature Medicine. These psychedelics appear to change how key networks in the brain connect, including those involved in higher-level thinking, sight and movement, and several drugs may share a common pattern of brain effects.

Psychedelic drugs are being investigated as scientific and clinical tools, but the brain mechanisms behind their effects remain unclear. Earlier brain imaging studies in small cohorts from single centres produced inconsistent findings, which made it difficult to identify effects that were reliable across studies and drugs. Understanding how psychedelics influence the brain’s functional connectivity — how activities in different parts of the brain fluctuate together over time — has therefore been unclear.

Manesh Girn, Danilo Bzdok, and colleagues combined 11 independent brain imaging datasets covering psilocybin, LSD, mescaline, DMT (N,N-dimethyltryptamine), and the DMT-containing brew, ayahuasca, in an analysis of 267 participants across more than 500 brain-scanning sessions. Across the various drugs and study sites, the clearest shared finding was that after participants took the drugs, connectivity became stronger between cortical brain networks involved in higher-level thinking (default mode and frontoparietal networks) and those involved in sight (visual networks) and touch (somatomotor networks).

While previous claims include that individual brain networks “disintegrate” under psychedelics, such effects were relatively inconsistent and seen only in some cases. The authors also found changes in connectivity between subcortical brain regions that help coordinate perception and action, including the caudate, putamen and cerebellum.  These results are consistent with the idea that psychedelics relax the brain’s usual top-down control, allowing activity to flow more freely. They also provide a more detailed picture, showing that these effects occur in specific patterns of networks and brain regions.

The findings provide a valuable resource for researchers seeking to better understand how psychedelics act on the brain and how these effects might be translated into clinically meaningful interventions. The results also point to a shared pattern of brain activity across multiple psychedelic drugs, offering a clearer picture of how the drugs reshape large-scale brain organisation. The authors note that future studies should directly compare different psychedelics under standardized conditions, using consistent methods and larger cohorts, to build a more robust and reliable map of their effects on the brain.

• Article
• Open access
• Published: 06 April 2026

Girn, M., Doss, M.K., Roseman, L. et al. An international mega-analysis of psychedelic drug effects on brain circuit function. Nat Med (2026). https://doi.org/10.1038/s41591-026-04287-9

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