Organicity Measures Following Repeated LSD Ingestion

Two animal experiments show that large doses of LSD can cause long-lasting changes in brain function that persist well beyond the time the drug is normally eliminated from the body. Cats given a single dose of 80 µg/kg showed disrupted conditioned responses and brain wave changes lasting 20 days. Squirrel monkeys given daily doses of 10 to 40 µg/kg required four to six months after stopping the drug to regain their previous skill level on difficult visual size discrimination tasks. A replication using a larger sample and doses from 10 to 100 µg/kg found similar impairment lasting several weeks.

Study at a glance

Abstract

TWO animal experiments have indicated that relatively large doses of lysergic acid diethylamide (LSD) can produce changes in central nervous system (CNS) function which persist for periods of time considerably longer than are usually estimated as necessary for drug detoxication. Adey1reports cats given a single dose of LSD in amounts of 80µg/kg showed disruption of conditioned responses and accompanying electroencephalographic (EEG) changes which persisted for 20 days. Sharpe et al2found that two of four squirrel monkeys given daily doses of from 10 to 40µg/kg required four to six months after discontinuing the drug to regain the predrug level of proficiency for difficult visual size discrimination tasks. Otis replicated this experiment using a larger sample and doses of frim 10 to 100µg/kg. He found similar impairment of both easy and difficult discrimination lasting for several weeks (L.S. Otis, written communication, March 7, 1969). Single