Comparing triggers to visual disturbances among individuals with positive vs negative experiences of hallucinogen-persisting perception disorder (HPPD) following LSD use.

BACKGROUND AND OJECTIVE Exploring differences in visual disturbances and triggers between Hallucinogen-Persisting-Perceptual-Disorder (HPPD) Type I ("positive/benign") and II ("negative/distressing"). METHODS Forty individuals with HPPD and prior LSD use completed clinical questionnaires. RESULTS The most common type of visual disturbances among individuals with HPPD I and II was slow movement of still objects and trailing phenomena, respectively. Those with HPPD I were more likely to report experiencing disturbances in dark environment, while looking at a still or moving object and during sexual intercourse. DISCUSSION AND CONCLUSIONS HPPD I and II differ in terms of visual disturbances and triggers, possibly representing different phenomena existing on the same spectrum. SCIENTIFIC SIGNIFICANCE Our study indicating differences in triggers to HPPD I and II adds to existing literature on differences in visual disturbances between the two subtypes. Further research elucidating additional differences between the subtypes of HPPD is needed. (Am J Addict 2017;26:568-571).