HPPD

Hallucinogen Persisting Perception Disorder (HPPD) refers to a set of persistent or recurrent visual disturbances that follow the use of hallucinogenic substances. The most commonly reported symptoms are geometric patterns, flashes of color, afterimages or trailing phenomena, halos around objects, micropsia or macropsia, and heightened sensitivity to light or motion. These visual effects can be distressing and may occur despite the absence of ongoing drug intoxication.

Onset and course vary. Symptoms may begin during or after hallucinogen use and can persist for weeks, months, or even years after last exposure. They may be intermittent, worsened by fatigue, stress, or sensory deprivation, and can fluctuate in intensity over time. Some individuals experience significant anxiety or impairment as a result.

Causes and risk factors are not well understood. The condition is thought to involve lasting changes in visual processing pathways and serotonergic systems, but precise mechanisms remain uncertain. A history of substantial or repeated hallucinogen exposure is a common factor, and coexisting psychiatric conditions can influence presentation and prognosis.

Diagnosis is clinical and involves a careful history of psychedelic use, symptom description, and exclusion of alternative explanations such as migraine, epilepsy, brain injury, or other substance effects. In the DSM-5-TR, Hallucinogen Persisting Perception Disorder is listed as a condition for further study rather than a fully established disorder; there are no universally accepted diagnostic criteria.

Treatment focuses on reassurance and avoidance of further hallucinogen use. Management may include addressing comorbid anxiety or mood symptoms, cognitive-behavioral therapy, and supportive care. Pharmacologic options have limited evidence and are considered case-by-case. Prognosis is variable; many cases gradually improve over time, while others persist.