The psychedelic afterglow phenomenon: a systematic review of subacute effects of classic serotonergic psychedelics.

Results support narrative reports of a subacute psychedelic 'afterglow' phenomenon comprising potentially beneficial changes in the perception of self, others, and the environment. Subacute adverse events were mild to severe, and no serious adverse events were reported. Many studies, however, lacked a standardized assessment of adverse effects. Future studies are needed to investigate the role of possible moderator variables and to reveal if and how positive effects from the subacute window may consolidate into long-term mental health benefits.