"The Banshee Chapter" starts out documentary-style, with words on the screen informing us of the secret CIA program from the 1950s and 1960s codenamed Project MKUltra, which involved chemists and doctors injecting hallucinogenic drugs into people in order to study the results. MKUltra was officially sanctioned in 1953 and halted twenty years later. Records of this program are hard to come by (in the wake of the Watergate scandal, CIA director Richard Helms ordered all MKUltra files destroyed), although there were Senate hearings on the topic in 1977, led by Ted Kennedy.
One of the goals listed on a surviving MKUltra document was to give people "substances which will promote illogical thinking and impulsiveness to the point where the recipient would be discredited in public" or, even more comforting, "materials which will cause temporary/permanent brain damage and loss of memory.