Psilocybin, the active compound in magic mushrooms, produces ego-dissolution—a feeling that the self is disintegrating or that the boundary between self and world is dissolving—similar to ego-disturbances seen in schizophrenia. In a placebo-controlled study of 15 healthy volunteers, functional MRI scans showed that psilocybin-induced ego-dissolution was linked to decreased connectivity between the medial temporal lobe and high-level cortical regions, disintegration of the salience network, and reduced communication between brain hemispheres. Individuals with lower diversity of executive network nodes at baseline were more likely to experience ego-dissolution. These findings suggest that maintaining a coherent sense of self depends on normal functioning of these brain systems.
Psychedelic drug use shows only a weak association with psychosis-like symptoms, largely explained by psychiatric comorbidities and use of other psychoactive substances. In a study of 1,032 adults (701 healthy young adults aged 18–35), psychedelic users had slightly higher schizotypy scores, but the effect was small and not significant after controlling for other drug use. Experimental testing in 39 subjects found that greater lifetime psychedelic exposure was linked to better evidence integration and heightened fear responses to instructed knowledge in a learning task, suggesting possible therapeutic effects on flexibility and aversive learning in non-psychotic populations.