<unk>  or<unk>  is a psychological disorder characterized by a continual presence of visual disturbances that are reminiscent of those generated by the ingestion of hallucinogenic substances.  Previous use of hallucinogens is a necessary, though not sufficient, cause for the disorder. <unk>  is distinct from flashbacks by reason of its relative permanence; whereas the latter is transient, the effects of<unk>  occur for a prolonged or indefinite period.
Hallucinogen persisting perception disorder
Opioid indications
Other hallucinogen use disorder
Amnesia pathophysiology
Amphetamine psychosis
Amnesia causes
Avoidant or restrictive food intake disorder
Munchausen by Internet