In the 1950s the US government did a lot of experiments with psychotomimetic drugs (in fact, as anybody who’s seen or read ‘The Men Who Stare At Goats’ will know, the US government used to do all sorts of weird and wonderful experiments). One of these experiments included feeding human test subjects measured quantities of LSD and then monitoring their ensuing behavior.

Source: 1950s Experiment Asked Artist To Take LSD And Draw The Same Portrait 9 Times, And Each Portrait Got Crazier