Effects of LSD, DMT and psilocybin on cognitive and psychological functions: a systematic review of the literature

Abstract

Objective: To carry out a systematic review of modern-era (1990-2025) placebo-controlled studies assessing the acute and post-acute effects of LSD, DMT and psilocybin on cognitive and psychological functions. Method: From February 28 to March 19, 2025, PubMed and APA PsychINFO were systematically searched for placebo-controlled studies examining how psychedelics influence empathy, reaction time, emotional processing, memory, cognitive flexibility and related cognitive functions. Additional searches were done in Google Scholar. Results: The systematic review included 30 studies. Psychedelics tended to enhance emotional empathy, but had no effect on cognitive empathy. Psychedelics impaired, enhanced or had no effect on memory depending on the task and timing of the assessment. Dose-dependent impairments were seen in many of the reaction time tasks, although some studies found no effects. Some studies found impaired recognition of negative stimuli under the acute effects of psychedelics. The findings regarding cognitive flexibility were mixed. Limitations: Many studies had small samples and it is hard to find a reliable placebo due to psychedelics’ unique subjective effects. Future studies should use bigger samples and also study more longitudinal effects of psychedelics on cognitive and psychological functions.