In cases where this causes distress or impairment it is diagnosed as hallucinogen persisting perception disorder (HPPD). Common effects include visual snow and palinopsia. It is possible for LSD to induce either intermittent or chronic visual hallucinations, in spite of no further use. LSD is active in small amounts relative to other psychoactive compounds with doses measured in micrograms. Adverse psychological reactions are possible, such as anxiety, paranoia, and delusions. Despite this, the US government made it illegal as part of the 'War on Drugs' after experimenting on people with it during MKULTRA.

LSD is considered to be non-addictive with low potential for abuse. It is most often sold on blotter paper and less commonly as tablets, in a watery solution or in gelatin squares called panes. LSD is typically either swallowed or held under the tongue. LSD is both the prototypical psychedelic and one of the 'classical' psychedelics, being the psychedelics with the greatest scientific and cultural significance. It is used mainly as a recreational drug or for spiritual reasons. LSD is also capable of causing mystical experiences and ego dissolution. Effects typically begin within half an hour and can last for up to 20 hours (although on average the trip lasts 8-12 hours). Dilated pupils, increased blood pressure, and increased body temperature are typical. At sufficiently high dosages LSD manifests primarily mental, visual, as well as auditory, hallucinations.

Effects typically include intensified thoughts, emotions, and sensory perception. Lysergic acid diethylamide, commonly known as LSD (from German Lysergsäure-diethylamid) and known colloquially as acid, is a potent psychedelic drug.

Street price for blotter acid