April 13th, 1953 was the birth date of project MK-ULTRA where the CIA sought out techniques of mind control and hypnosis to rival those which had been used in the Korean War by the Soviets, Chinese, and North Koreans on American Prisoners of War. The project continued on through at least the late 1960's, used american citizens as test subjects, and experimented with different kinds of drugs, most notoriously LSD. The CIA was interested in using these techniques on their own captives, as well as figuring out a way to use these techniques to manipulate foreign leaders. They later tried to invent a scheme to drug Cuban cigar smoker Fidel Castro.
A couple of well known subjects of the MKULTRA experiments were Unabomber Ted Kazynski and Merry Prankster Ken Kesey, author of One Flew Over the Cuckoo's Nest. James "Whitey" Bulger, Irish mob boss, volunteered for testing while serving a prison term for armed robbery and hijacking, in order to lessen his sentence. For the most part, however, the experiments were performed without the subjects knowledge, drugging their food, drinks, cigarettes, whatever way the unknowing person could be dosed without knowing about it.
The project was kept secret until 1975, when an investigation by the Church Commitee (led by Senator Frank Church), and another one by the Rockefeller Commission, brought their findings before Congress. The overall investigation was hampered, however, by the fact that CIA director Richard Helms had ordered all MK-ULTRA files destroyed in 1973.