Psilocybin effects on brain functional connectivity: a systematic review of fMRI studies

Psilocybin-assisted therapies are innovative therapeutic approaches, particularly in the treatment of depression. However, there are sparse studies providing functional magnetic resonance imaging (fMRI) evidence elucidating the underlying biological mechanisms that support clinical outcomes. This review aims to comprehensively gather all the evidence reported in psilocybin studies using fMRI techniques. Independent extraction of articles was conducted by 2 authors using predefined data fields. 20 unique datasets were identified, with 5 including participants diagnosed with depression. Dropout rates were found to be high, and follow-up scanning timepoints were lacking in most of the studies. Most research has focused on the amygdala, the anterior cingulate cortex and the prefrontal cortex, as key regions involved in the effects of psilocybin. However, the current literature exhibits inconsistency in methods and designs. Further research is necessary to better define psilocybin’s impact on the human brain and its potential to enhance psychotherapy outcomes.