Hallucinogen Persisting Perception

Hallucinogen persisting perception disorder (HPPD) is a chronic disorder in which a person has non-psychotic flashbacks of visual hallucinations or distortions experienced during a previous hallucinogenic drug experience, usually lacking the same feelings of mental intoxication experienced before.


Cluster Number:
Wiki Number: W092
Diagnosis: Hallucinogen-Persisting Perception Disorder
US Patients:
World Patients:
Sex Ratio:
Age Onset:
Brain Area:
Symptoms: non-psychotic flashbacks of visual hallucinations from previous drug expereinces; often visual snow as distracting lights
Causes: prior use of hallucenogenic drugs, mescaline, MDMA (ecstasy)
Medications: cannabis worsens the effects; sedatives, sobriety from all psychoactive substances appears best
Therapies: talk therapy may help. 1 in 500,000 users may have chronic occurrences.


The world-wide medical research
reports chosen for each diagnosis 

Clicking each title opens the
PubMed article’s summary-abstract.

  • Visual Phenomena Associated With Migraine and Their Differential Diagnosis
    by Ozan E Eren on October 12, 2021

    CONCLUSION: Patients with visual phenomena typically consult physicians from various medical specialties. A correct differential diagnosis can be made based on the history if the physician views the symptoms in their overall context to determine the particular disease entity that is responsible.

  • On Perception and Consciousness in HPPD: A Systematic Review
    by Pieter J Vis on August 30, 2021

    Hallucinogen-persisting perception disorder (HPPD) features as a diagnostic category in the DSM-5, ICD-11, and other major classifications, but our knowledge of the phenomenology of the perceptual symptoms involved and the changes in consciousness during the characteristic "flashbacks" is limited. We systematically evaluated original case reports and case series on HPPD to define its phenomenology, associated (psycho)pathology, and course. Our search of PubMed and Embase yielded 66 relevant...

  • Migraine prevalence in visual snow with prior illicit drug use (hallucinogen persisting perception disorder) versus without
    by Robin M van Dongen on May 12, 2021

    CONCLUSIONS: Whereas none of the HPPD participants had migraine, more than half of the visual snow controls without prior use of illicit drugs had migraine. This suggests that at least partly different pathophysiological factors play a role in these disorders. Users of ecstasy and other hallucinogens should be warned of the risk of visual snow. Further studies are needed to enhance understanding of the underlying neurobiology of HPPD and VSS to enable better management of these conditions.

  • Harnessing psilocybin: antidepressant-like behavioral and synaptic actions of psilocybin are independent of 5-HT2R activation in mice
    by Natalie Hesselgrave on April 14, 2021

    Depression is a widespread and devastating mental illness and the search for rapid-acting antidepressants remains critical. There is now exciting evidence that the psychedelic compound psilocybin produces not only powerful alterations of consciousness, but also rapid and persistent antidepressant effects. How psilocybin exerts its therapeutic actions is not known, but it is widely presumed that these actions require altered consciousness, which is known to be dependent on serotonin 2A receptor...