Hallucinogen Persisting Perception Disorder

Hallucinogen Persisting Perception Disorder, what many refer to as “flashbacks” from taking hallucinogenic drugs, was first listed in the 1986 DSM-III.  The DSM-IV criteria for HPPD include the following: re-experiencing one or more of the perceptual effects of the hallucinogen after cessation of use, those symptoms causing distress or impairment in important situations, and the symptoms not being attributed to any other medication or mental disorder. While HPPD is documented as true, its uncommon nature makes it hard to study.

There are many problems when it comes to HPPD and “flashbacks,” one of the biggest being the lack of solid definition for a flashback.  In many of the studies done thus far, the criterion for HPPD was not yet determined, so it is hard to say which cases are legitimate. Also, other psychiatric issues or drug abuse were frequently reported making it hard to differentiate the reason behind the perceptions that subjects were experiencing.  Another conflict was that many of the perceptions that were reported were mild and possibly not caused from LSD.  The real question that we are left with is why do these flashbacks occur? Researchers have not found a correlation between the amount of exposure to hallucinogens and the flashbacks that occur.

Overall, it is definitely true that some people that have used LSD have experienced some sort of flashback to the perceptual experiences they had while using the drug.  The studies that have been done to prove this is so are spotty at best.  They know that it happens, but they’ve yet to pinpoint exactly why.

John H Halpern, Harrison G Pope Jr, Hallucinogen persisting perception disorder: what do we know after 50 years?, Drug and Alcohol Dependence, Volume 69, Issue 2, 1 March 2003, Pages 109-119, ISSN 0376-8716, http://dx.doi.org/10.1016/S0376-8716(02)00306-X.
(http://www.sciencedirect.com/science/article/pii/S037687160200306X)