B. The symptoms in Criterion A cause clinically significant distress or impairment in so- cial, occupational, or other important areas of functioning.
C. The symptoms are not attributable to another medical condition (e.g., anatomical le- sions and infections of the brain, visual epilepsies) and are not better explained by an- other mental disorder (e.g., delirium, major neurocognitive disorder, schizophrenia) or hypnopompic hallucinations.
The hallmark of hallucinogen persisting perception disorder is the reexperiencing, when the individual is sober, of the perceptual disturbances that were experienced while the individ- ual was intoxicated with the hallucinogen (Criterion A). The symptoms may include any perceptual perturbations, but visual disturbances tend to be predominant. Typical of the ab— normal visual perceptions are geometric hallucinations, false perceptions of movement in the peripheral visual fields, ﬂashes of color, intensified colors, trails of images of moving ob- jects (i.e., images left suspended in the path of a moving object as seen in stroboscopic pho- tography), perceptions of entire objects, positive afterimages (i.e., a same-colored or complementary-colored ”shadow” of an object remaining after removal of the object), halos around objects, or misperception of images as too large (macropsia) or too small (micropsia).
Duration of the visual disturbances may be episodic or nearly continuous and must cause clinically significant distress or impairment in social, occupational, or other important areas of functioning (Criterion B). The disturbances may last for weeks, months, or years. Other explanations for the disturbances (e.g., brain lesions, preexisting psychosis, seizure disor- ders, migraine aura without headaches) must be ruled out (Criterion C).
diethylamide) use, but not exclusively. There does not appear to be a strong correlation be- tween hallucinogen persisting perception disorder and number of occasions of hallucino- gen use, with some instances of hallucinogen persisting perception disorder occurring in individuals with minimal exposure to hallucinogens. Some instances of hallucinogen per- sisting perception disorder may be triggered by use of other substances (e.g., cannabis or alcohol) or in adaptation to dark environments.
Reality testing remains intact in individuals with hallucinogen persisting perception dis- order (i.e., the individual is aware that the disturbance is linked to the effect of the drug).
If this is not the case, another disorder might better explain the abnormal perceptions.
Prevalence estimates of hallucinogen persisting perception disorder are unknown. Initial prevalence estimates of the disorder among individuals who use hallucinogens is approx- imately 4.2%.
Little is known about the development of hallucinogen persisting perception disorder. Its course, as suggested by its name, is persistent, lasting for weeks, months, or even years in certain individuals.
There is little evidence regarding risk factors for hallucinogen persisting perception dis- order, although genetic factors have been suggested as a possible explanation underlying the susceptibility to LSD effects in this condition.
some cases, many individuals with the disorder are able to suppress the disturbances and continue to function normally.
Conditions to be ruled out include schizophrenia, other drug effects, neurodegenerative disorders, stroke, brain tumors, infections, and head trauma. Neuroimaging results in hal- lucinogen persisting perception disorder cases are typically negative. As noted earlier, re- ality testing remains intact (i.e., the individual is aware that the disturbance is linked to the effect of the drug); if this is not the case, another disorder (e.g., psychotic disorder, another medical condition) might better explain the abnormal perceptions.
disorder are panic disorder, alcohol use disorder, and major depressive disorder.