Central Intelligence Agency documents suggest that the agency considered and explored uses of radiation for the purpose of mind control as part of MKULTRA. Other early efforts focused on LSD, which appears to have formed the majority of research as time went on. Experiments included dosing CIA employees, military personnel, other government agents, prostitutes, mental patients, and members of the general public with LSD to study their reactions, usually without the subject's knowledge.
Some subjects' participation was consensual, and in these cases, the subjects appeared to be singled out for even more horrific experiments. In one case, a selection of volunteers was given LSD for 77 days straight.
Another technique was connecting a barbiturate IV into one arm and an amphetamine IV into the other. The barbiturates were released into the subject first, and as soon as the subject began to fall asleep, the amphetamines were released. The subject would begin babbling incoherently at this point, and it was sometimes possible to ask questions and get useful answers. This treatment was discarded as it often resulted in the death of the patient from physical side effects of the drug combination, making further interrogation impossible. Other experiments involved heroin, mescaline, psilocybin, scopolamine, marijuana, alcohol, and sodium pentothal.