532 Substance-Related and Addictive Disorders
Development and Course
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. 
Risk and Prognostic Factors
There is little evidence regarding risk factor s 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. 
Functional Consequences of 
Hallucinogen Persisting  Perception Disorder
Although hallucinogen persisting perception  disorder remains a chronic condition in
some cases, many individuals with the disord er are able to suppres s the disturbances and
continue to function normally. 
Differential Diagnosis
Conditions to be ruled out include schizophrenia, other drug  effects, neurodegenerative
disorders, stroke, brain tumors, infections, an d 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 ex plain the abnormal perceptions. 
Comorbidity
Common comorbid mental disorders accomp anying hallucinogen persisting perception
disorder are panic disorder , alcohol use disorder, and major depressive disorder. 
Other Phencyclidine-Induced Disorders
Other phencyclidine-induced diso rders are described in other chapters of the manual with
disorders with which they share phenomeno logy (see the substance/medication-induced
mental disorders in these chap ters): phencyclidine-induced psychotic disorder (“Schizo-