ABSTRACT
Chronic adverse reactions to recreational drug ingestion, in the absence of ongoing usage, are less common, although these have been documented after use of hallucinogenic substances such as LSD (Abraham, 1983), psilocybin (mushrooms) (Espiard, Lecardeur, Abadie, Halbecq, & Dollfus, 2005), ecstasy (Van Kampen & Katz, 2001), and cannabis (Keeler, Reifler, & Liptzin, 1968). Of particular interest following hallucinogen use is the phenomenon of ‘drug flashbacks’ (Abraham, 1983), affecting a minority of individuals who have taken the substance, which can persist for months or even years after the ingestion. DSM-IV recognizes a syndrome called hallucinogen persisting perception disorder (HPPD; Flashbacks; American Psychiatric Association, 1994). The hallmark symptom here is re-experiencing of one or more perceptual symptoms of the original drug experience, such as geometric hallucinations, false perceptions of movement, or flashes of colour. The diagnosis is withheld if there is a failure in reality testing, as in a psychotic illness. Therefore, the person recognizes that the flashbacks are drug effects. The DSM-IV diagnostic criteria for HPPD are:
A The re-experiencing, following cessation of use of a hallucinogen, of one or more of the perceptual symptoms that were experienced while intoxicated with the hallucinogen (e.g., geometric hallucinations, false perceptions of movement in the peripheral visual fields, flashes of colour, intensified colours, trails of images of moving objects, positive afterimages, halos around objects, macropsia, and micropsia).
