hallucinogen persisting perception disorder

According to the DSM-IV, hallucinogen persisting perception disorder's essential "feature is the transient recurrence of disturbances in perception that are reminiscent of those experiences during one or more earlier Hallucinogen Intoxication (Criterion A)." This is without the use of hallucinogens at the time or any other signs of another disorder with hallucinations as a symptom. The hallucinations that occur episodically may be self-induced or triggered by entry into a dark environment, various drugs, anxiety or fatigue, or other stressors. People suffering from HPPD report seeing geometric shapes on plain backgrounds such as walls; intense colors; objects trailing behind stationary objects; flashes of light; and the movement of still objects.  People can develop HPPD after just one use of a  hallucinogenic, the most common being LSD.  Although researchers are trying to use various drugs to help the effects of HPPD, the only real treatment is to wait for HPPD to subside on its on and to stay away from hallucinogenic drugs.

This Video is about LSD and its effects, since LSD is the main cause of HPPD. Although it does not depict HPPD, I thought it was a good representation of what the hallucinations could be like that could result in you suffering from the disorder.

http://www.erowid.org/chemicals/lsd/lsd_health2.shtml
http://www.neurosoup.com/hallucinogen-persisting-perception-disorder-hppd/