- flashback, drug related
- Also known as flashback phenomenon. The introduction of the term flashback is attributed to the American psychiatrist Mardi Jon Horowitz (b. 1934). Horowitz used the term in 1969 to denote a return of hallucinations, *illusions, or * sensory distortions after the use of a * hallucinogen - or, more specifically, after the immediate effects of a hallucinogen have worn off. As Horowitz maintains, "Flashbacks are peremptory and recurrent intrusions into awareness long after the ingested drug has worn off. The most common and clearest content of the flashbacks seems to involve the visual sensory system, but flashbacks have been reported in any sensory modality: taste, smell, touch, kinesthet-ics, vestibular changes, and auditory images. In addition, distortions of time sense, self-image, or reality sense may occur." Since the 1970s the term flashback has been used to denote any * sensory deception or distortion that may arise either as a consequence of the prior use of a chemical substance, as a consequence of electrical stimulation of the cortex, or in the context of post-traumatic stress disorder (PTSD). For the latter type of flashback, see the entry Post-traumatic flashback. For flashbacks as a consequence of electrical stimulation, see the entry Cortical probing and hallucinations. The drug-related type of flashback can occur up to months or even years after the exposure to a *deliriant or other * hallucinogen. Some examples of deliriants associated with flashback phenomena are ergine, harmaline, harmine, ibogaine, ketamine, LSD, mescaline, ololiuqui, PCP, psilocin, and psilocybin. Drug-related flashback phenomena tend to occur to the waking mind, and to a clear sensorium, although it has been suggested that the incidence of LSD-induced flashbacks is higher during episodes of cannabis intoxication. They typically last for a fraction of a second to several minutes. Their nature and content can be as diverse as the acute effects of hallucinogen intoxication. They tend to be experienced in the form of exact phenomenological replicas of prior perceptual experiences, but they can also evolve into, or be replaced by, novel images. Attempts at system-atization have yielded a rudimentary subdivision of flashbacks into visual flashbacks, somatic flashbacks, and emotional flashbacks. The group of visual flashbacks has been further divided into visual distortions, heightened imagery, and *visual hallucinations. Horowitz himself proposed a dichotomous subdivision of flashbacks, yielding a category dubbed 'spontaneous return of perceptual distortions', and a second one dubbed 'increased susceptibility to spontaneous imagery'. The American psychopharmacologist Henry David Abraham distinguishes no fewer than 16 categories of visual distortions occurring in the context of visual flashbacks, comprising acquired colour confusion, dyslexia due to positive and negative * afterimages interfering with the reading process, flashes of colour, * geometric hallucinations such as sparkles, visual fireworks, *lattices, and large, transparent blobs (referred to by Abraham as * pseudohallucinations), geometric * phosphenes, * halos around objects, * illusions of movement, * imagistic phosphenes, intensified colours (i.e. *hyperchromatopsia), *macropsia, *micropsia, *negative afterimages, *positive afterimages, *pareidolias, *trailing phenomena, and peripheral percepts. The visual hallucinations of flashback imagery tend to be *geometric or *complex in nature, whereby the latter depict people, faces (i.e. *facial hallucinations), animals (i.e. *zoopsia), landscapes, and so on. Individuals having experienced flashbacks tend to report that their phenomenological qualities are different from regular sense perceptions, and that their content tends to be frightening in nature. The lifetime prevalence of flashbacks in cross-sectional studies among former and present LSD users is reported to range from 15 to 77%. As to their pathophysiology, various hypotheses have been proposed, the most important ofwhich is a variant of the * perceptual release theory. It has been suggested that flashbacks may be related conceptually as well as phenomenolog-ically (and perhaps also pathophysiologically) with other mnestic events such as *hallucinogen-induced persistent perception disorder (HPPD), *flashbacks in PTSD, *palinopsia, * reperceptive hallucinations, * phantom pain, * eidetic imagery, and * flashbulb memories.ReferencesAbraham, H.D. (1983). Visual phenomenology of the LSD flashback. Archives of General Psychiatry, 40, 884-889.Horowitz, M.J. (1969). Flashbacks: Recurrent intrusive images after the use of LSD. American Journal of Psychiatry, 126, 565-569.Sierra, M., Berrios, G.E. (2000). Flashbulb and flashback memories .In: Memory disorders in psychiatric practice. Edited by Berrios, G.E., Hodges, J.R. Cambridge: Cambridge University Press.
Dictionary of Hallucinations. J.D. Blom. 2010.