Hallucinogen persisting perceptual disorder: a scoping review covering frequency, risk factors, prevention, and treatment

Hallucinogen persisting perception disorder (HPPD) affects a subset of persons who use hallucinogens and is defined as the repeated experience of hallucinations and other perceptual disturbances as a result of prior intoxications. As select hallucinogens are under development for the treatment of selectmental disorders, there is a need to better characterize this disorder. A scoping review of the literature on HPPD was completed from inception to July 2021. Topics covered in the review herein include treatments for HPPD, prevalence or incidence data on HPPD among different classes of hallucinogens, risk factors for HPPD, and data pertaining to the pathophysiology of HPPD. Hallucinogen persisting perception disorder appears to be an uncommon yet serious event associated with prior hallucinogen exposure. The renewed interest in psychedelics as potential treatment options for select mental disorders, especially agents with hallucinogenic potential, provides the impetus to characterize HPPD in its frequency, risk and protective factors, key characteristics, as well as other clinical and treatment-related factors.