Sidney Cohen, MD (7 Jun 1910 – 8 May 1987) was an American psychiatrist, professor of medicine, and author,[1] known as a leading expert on LSD, marijuana, cocaine, and other mood altering drugs.
[4] After completing his internship he joined the U.S. Army Medical Corps, extensively participated in the WW II Pacific campaign, and was eventually promoted to colonel.
From 1968 to 1970 he was on academic leave of absence when he was appointed by Richard Nixon in 1968 as the first director of the NIMH's Division of Narcotic Abuse and Drug Addiction.
[4] Sidney Cohen is perhaps most well-known in popular culture for LSD experiments he conducted with Keith Ditman, Betty Eisner and Gerald Heard, based on correspondence with Humphrey Osmond, in the mid-1950s.
After becoming convinced that use of LSD could be dangerous, particularly if unsupervised, Cohen maintained a public anti-LSD stance and sometimes testy discourse with Timothy Leary.