Diagnostic criteria of HPPD

According to a review from Halpern and Pope (2003), "'Flashbacks' following use of hallucinogenic drugs have been reported for decades; they are recognized in DSM-IV as 'Hallucinogen Persisting Perception Disorder (Flashbacks)', or HPPD. We located and analyzed 20 quantitative studies between 1955 and 2001 examining this phenomenon. However, many of these studies were performed before operational criteria for HPPD were published in DSM-III-R, so they are difficult to interpret in the light of current diagnostic criteria. Overall, current knowledge of HPPD remains very limited. In particular (1) the term 'flashbacks' is defined in so many ways that it is essentially valueless; (2) most studies provide too little information to judge how many cases could meet DSM-IV criteria for HPPD; and consequently (3) information about risk factors for HPPD, possible etiologic mechanisms, and potential treatment modalities must be interpreted with great caution. At present, HPPD appears to be a genuine but uncommon disorder, sometimes persisting for months or years after hallucinogen use and causing substantial morbidity. It is reported most commonly after illicit LSD use, but less commonly with LSD administered in research or treatment settings, or with use of other types of hallucinogens. There are case reports, but no randomized controlled trials, of successful treatment with neuroleptics, anticonvulsants, benzodiazepines, and clonidine. Although it may be difficult to collect large samples of HPPD cases, further studies are critically needed to augment the meagre data presently available regarding the prevalence, etiology, and treatment of HPPD."

Dr. Henry David Abraham described the "Visual phenomenology of the LSD flashback" in 1983 (see Abraham, 1983, and the HPPD summary at Dr. Abraham's homepage). The formerly used term LSD flashback should be replaced by the term HPPD, because, as Abraham et al. (1996) remarked, "flashback appears to be a misnomer, as patients described cases of continuous, rather than paroxysmal, visual disturbances from LSD" (p. 292).

The above drawing from an HPPD patient of Dr. Abraham illustrates visual hallucinations described by the sufferer as countless "shimmering, flowing" dots floating in the air, "a pervasive part of my entire visual field". This type of hallucination, in which the patient literally "sees the air", was called "aeropsia" by Abraham (1983).

Aeropsia and visual snow

"The question of 'visual snow' is a bit of a quibble in language. I have previously described this symptom and called it 'aeropsia' because of the patients' propensity to say it was like 'seeing the air.' Perhaps my term is a bit too stuffy for lay use. I see them as interchangeable.'"

(Dr. Henry David Abraham, Email to Jacob, undated [2005]; cited by Jacob [subject #100], Ezboard forum Visual snow or static, hppd vs visual snow - (validation of VS), June 30, 2005)

Another HPPD sufferer, DOHP, described his visuals thus: "My most interesting OEV I get is from meditating, I made a very, very rough gif of what I see. To describe it further, it is like tiny blue balls of light/energy with a light blue/yellow trail behind it moving in different directions; when they reach the destination they dissapear and restart from where they were, this cycle takes around 1 second or less."

(DOHP, Bluelight - Focus Forums - Psychedelic Drugs - Describe your visuals..., June 5, 2007)

He added: "And it resembles almost the exact way brain signals/neurons interact, which makes me wounder if I am seeing the brain working. Does anybody else have the same visuals as this? As I am fascinated at how much it resembles brain neurons."

(DOHP, Bluelight - Focus Forums - Psychedelic Drugs - Describe your visuals..., June 5, 2007)

HPPD as a label

"The fact that I discovered a classification for my symptoms has helped immensely. It transformed the HPPD experience from a very private and personal struggle, ridden with uncertainty and fear, to one that is shared and transparent -- in the sense that I know what to expect, even in the long-term, and now realize that I am not a complete anomaly. The symptoms do indeed make me feel isolated at times but this is the product of having psychological difficulty while everyone else in my life appears to be free from such problems. Having been (self) diagnosed with HPPD does not publicly alienate me -- almost nobody knows I suffer from such issues and even if they do, they cannot really empathize or even understand the situation. And since my outward conduct has not really been affected, I can live a normal life. I felt far more 'different' and 'crazy' before discovering both the disorder and this board. Both of these things have provided me with basic knowledge and insight into the 'framework' of HPPD, which has allowed me to better address the matters at hand.

At times I still am overwhelmed by it -- almost exclusively due to anxiety attacks -- but such troubles would exist independent of whether or not you are diagnosed with HPPD; the problems precede the classification of the disorder."

(page of zeppelin, HPPD online - HPPD Forum - HPPD Support > HPPD General Support Section - HPPD as a Label, July 20, 2007)

References

Abraham HD. Visual phenomenology of the LSD flashback. Arch Gen Psychiatry 1983; 40: 884-889. [PDF]
Abraham HD, Aldridge AM, Gogia P. The psychopharmacology of hallucinogens. Neuropsychopharmacology 1996; 14: 285-298, 1996. [PDF]
American Psychiatric Association. Diagnostic and statistical manual of mental disorders: DSM-IV. 4th ed. American Psychiatric Association, Washington, DC 1994.
Halpern JH, Pope HG Jr. Hallucinogen persisting perception disorder: what do we know after 50 years? Drug Alcohol Depend 2003; 69: 109-119. [PDF]