This systematic review will collect and summarize studies on the psychological processes that may explain how psychedelic therapy helps treat depression. The review will search four databases for research involving classic psychedelics in adults with depression, focusing on studies that report or propose psychological mechanisms behind symptom improvement. Two reviewers will independently screen and assess the studies, then synthesize findings separately for empirical and non-empirical work. Because this is a new field, the review expects to find limited empirical research and variation among studies. The goal is to map the current evidence, identify gaps, and suggest variables for future investigation.
A planned systematic review will identify and summarize psychological processes that may explain how psychedelic therapy reduces depression symptoms. The review will search Scopus, PsycINFO, PubMed, and Web of Science for studies on classic psychedelics used to treat depression in adults, focusing on proposed psychological mechanisms of symptom change. Two authors will independently screen studies, assess quality, and extract data. Empirical and non-empirical research will be analyzed separately using narrative synthesis. The review aims to present the current state of evidence, identify gaps, and generate candidate variables for future research, acknowledging limitations such as study heterogeneity and a lack of empirical work.