In 1971, Raphael Mechoulam published a study documenting the very long-lasting analog of THC with a dimethyl-heptyl ‘tail’. However, in 1949, a project operating out of the Edgewood Arsenal developed a THC analog named Dimethylheptyl Pyran, which had the same feature. Given the strong incapacitating effects and a favorable safety margin, the project thought DMHP could be useful as an incapacitating agent. However, DMHP also produced severe hypotension and thus was abandoned.

However, good evidence indicates that the U.S. Central Intelligence Agency (CIA) conducted experiments on all the available hallucinogens in hopes of being able to produce Manchurian Candidates (brainwashed human weapons).

The CIA project, MK-Ultra covertly subjected numerous soldiers, and civilians to high doses of hallucinogens and other drugs usually without their consent. Other drugs tested include MDMA, ibogaine, atropine and scopolamine (Still, other projects released bacteria or viruses on unsuspecting regions or tested the injection of radioactive agents).

On August 15, 1951, residents of the French village, Pont-Saint-Esprit suddenly became afflicted with severe hallucinations. People developed physical symptoms and sometimes acute psychotic episodes. At least 250 people felt the effects, 50 people were committed to asylums, and at least four people died. Authorities blamed it on ergot poisoning, but documentation validated the use of Sandoz LSD by persons unknown.

In another project, Operation Midnight Climax, prostitutes lured men to a prepared bedroom where the men were surreptitiously given LSD and their reactions documented from behind a two-way mirror.

Fearing exposure, almost all of the records made documenting military use of hallucinogens were deeply classified or destroyed.