public first learned about MK-Ultra during the Church Committee hearings on the CIA held in
1975; further hearings on the program were held in 1977. However, most of the agency’s
documents on the program had been destroyed in 1973 on orders from director Richard Helms.
Mystical Experience Questionnaire: The psychological survey, developed by Walter Pahnke and
William Richards in the 1960s, used to assess whether a volunteer in a trial of a psychedelic drug
has undergone a mystical-type experience. It seeks to measure, on a scale of one to five, seven
attributes of a mystical experience: internal unity; external unity; transcendence of time and
space; ineffability and paradoxicality; a sense of sacredness; the noetic quality; and a deeply felt
positive mood. Several revised versions of the MEQ have since been developed.
noetic quality: A term introduced by William James, an American psychologist, to denote the fact
that the mystical state registers not only as a feeling but as a state of knowledge. People emerge
with the enduring conviction that important truths have been revealed to them. The noetic quality
was, for James, one of the four marks of the mystical experience, along with ineffability,
transiency, and passivity.
phenethylamines: A class of organic molecule, and the name for one of the two principal types of
psychedelic compounds; the other is the tryptamines. Mescaline and MDMA are examples of
phenethylamines.
psilocin: One of the two principal psychoactive compounds found in psilocybin mushrooms. The
other is psilocybin, which breaks down to psilocin under certain conditions. Both compounds
were isolated (from mushrooms provided by R. Gordon Wasson) and named by Albert Hofmann
in 1958. Psilocin is what gives psilocybin mushrooms their bluish tint when bruised.
Psilocybe: A genus of approximately two hundred gilled mushrooms, roughly half of which
produce psychoactive compounds such as psilocybin and psilocin. Psilocybes are distributed
throughout the world. Their possession is illegal in most jurisdictions. The best-known members
of the genus are Psilocybe cubensis, Psilocybe cyanescens, Psilocybe semilanceata, and Psilocybe
azurescens.
psilocybin: The main psychoactive compound found in psilocybin mushrooms and a shorthand
for the class of mushrooms that contain it.
psychedelic: From the Greek for “mind manifesting.” The term was coined in 1956 by Humphry
Osmond to describe drugs like LSD and psilocybin that produce radical changes in consciousness.
psycholytic: A term coined in the 1960s for a drug, or dose of a drug, that loosens constraints on
the mind, allowing subconscious material to enter one’s awareness. Also the name for a form of
psychotherapy that uses low doses of psychedelics to relax the patient’s ego without obliterating it.
psychotomimetic: The name for a drug that produces effects resembling psychosis. This was a
common term for LSD and drugs like it when they were first introduced to psychiatry in the
1950s; researchers believed they produced temporary psychoses that would yield insights into the
nature of mental illness and give therapists the opportunity to experience madness firsthand.
reducing valve: The term used by Aldous Huxley in The Doors of Perception for the mental filter
that admits to our awareness only a “measly trickle of the kind of consciousness” we need to
survive. In his view, the value of psychedelics was to open the reducing valve, giving us access to
the fullness of experience and the universal “Mind at Large.”