Acute psychotic syndromes in adolescents are rarely due to intoxications with hallucinogenic drugs, but the clinical relevance of flashback phenomena as a post-hallucinogenic psychiatric disorder remains disputed. Because biogenic hallucinogens and LSD are increasingly popular among adolescents and young adults, knowledge of intoxications, resulting psychiatric disorders, medical complications, and therapeutic approaches is clinically important. Intoxications with drugs of herbal origin, such as tropane alkaloids, play an important role in emergency situations.
Flashbacks are brief visual, mood, and consciousness changes that resemble the effects of hallucinogens, often considered benign or pleasant by users. Hallucinogen persisting perception disorder (HPPD) is a visual perceptual disorder that can persist for months or years and cause severe distress. The prevalence of both flashbacks and HPPD is unknown, but few case reports have been published despite millions of hallucinogen users since the 1960s and 1970s. The exact causes of HPPD remain unclear, and it is considered a puzzling disorder. Different consequences and new therapeutic approaches are discussed in clinical context.