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Hallucinogens are drugs like LSD (lysergic acid diethylamide), mescaline (the active ingredient of the peyote cactus), and psilocybin (the active ingredient of psycho­active mushrooms). They cause profound changes in thought processes similar to a waking dream or temporary psychosis.

What are hallucinogens? Entheogens?

Hallucinogens do not always cause hallucinations. Some specialists prefer the term psychedelic (mind-altering) for these drugs. The term entheogen (en-THEE-a-gen) is used more generally to refer to mind-altering plants used for spiritual or religious purposes.


LSD, lysergic acid diethylamide, is the most powerful psychoactive substance known to science. Tiny amounts of it, measured in micrograms (thousandths of a gram) produce powerful effects.

LSD was discovered accidentally in 1943 by Albert Hofmann of Sandoz Laboratories in Switzerland. While working on the synthesis of medically potent alkaloids, he began having strange sensations.

As he wrote later, in his journal:

Last Friday, April 16, 1943, I was forced to interrupt my work in the laboratory in the middle of the afternoon and proceed home, being affected by a remarkable restless­ness, combined with a slight dizziness....In a dreamlike state, with eyes closed...I perceived an uninterrupted stream of fantastic pictures, extraordinary shapes with intense, kaleidoscopic play of colors. After some two hours this condition faded away."

Hofmann speculated that some of the substance he was working on, LSD-25, had contacted his fingertip and was absorbed through the skin. He was doing research for a pharmaceutical company, and he knew a drug with such strong psychological effects could be important. He wrote:

If LSD-25 had indeed been the cause of this bizarre exper­ience, then it must be a substance of extraordinary potency. There seemed to be only one way of getting to the bottom of this. I decided on a self-experiment.

Hofmann deliberately drank a solution containing LSD. An hour and a half later he began his "most severe crisis."

...My surroundings had now transformed themselves in more terrifying ways. Everything in the room spun around, and the familiar objects and pieces of furniture assumed grotesque, threatening forms. They were in continuous motion, animated, as if driven by an inner restlessness.

The lady next door, whom I scarcely recognized, brought me milk; in the course of the evening I drank more than two liters. She was no longer Mrs. R. but rather a malevolent, insidious witch with a colored mask.

...I was seized by the dreadful fear of going insane. I was taken to another world, another place, another time. My body seemed to be without sensation, lifeless, strange. Was I dying? Was this the transition? At times I believed myself to be outside my body...

By the time the doctor arrived, the climax of my despondent condition had already passed. My laboratory assistant in­formed him about my self-experiment, as I myself was not yet able to formulate a coherent sentence.

He shook his head in perplexity, after my attempts to describe the mortal danger that threatened my body. He could detect no abnormal symptoms other than extremely dilated pupils....

Now, little by little I could begin to enjoy the unprecedented colors and plays of shapes that persisted behind my closed eyes. Kaleido­scopic, fantastic images surged in on me, alternating, variegating, opening and then closing themselves in circles and spirals, exploding in colored fountains, rearranging and hybridizing themselves in constant flux. (Hofman, 1980, p.15)

How did Albert Hofmann discover LSD?

Hofmann probably took a relatively large dose of LSD. The symptoms he exper­ienced are typical of a high-dosage LSD trip: kaleidoscopic images, feelings of being in a different reality or outside the body, and (in a "bad trip") a fear of going insane, paranoid ideas about health problems, exaggerated fears and anxieties.

After such experiences, Hofmann never suspected LSD would become a recreational drug. It was too powerful, and its effects were not pleasurable in any simple sense.

Hofmann saw LSD as a possible tool for artists or psychiatrists. He thought it might reveal normally unseen depths of the mind through a sort of temporary insanity.

Why did Hofmann doubt LSD would be used as a "recreational" drug?

LSD is notorious for producing traumatic "bad trips" in some people. However, these experiences are rare when the drug is given in pure form under controlled circumstances.

The United States Army and CIA tested LSD on hundreds of subjects. When the research suddenly became public in 1975, due to a lawsuit by a man who claimed lasting ill effects from his parti­cipation as a subject, Army drug experts hastened to reassure the public that the research was safe and most of the subjects experienced no harm. Newspaper reports like the following appeared.

Army Says LSD Not Dangerous

Army experiments with LSD showed the drug is powerful but not addictive and it changes body cells less than caffeine, according to a top researcher involved in the program.

Dr. Van M. Sim said he personally had tried LSD.

He told a Pentagon news confer­ence Wednesday only a few Army test subjects reported having after-effects from the hallucinogen.

The director of chemical warfare research at Edgewood Arsenal, Md. said LSD was admin­istered to 585 volunteers, mostly soldiers but includ­ing some civilian Army per­sonnel, over 12 years ending in 1967.

The Army previously had said possibly 900 other persons were tested by outside contractors as part of the program.

...The study, Sim said, found LSD is a powerful drug that civilians might use for enjoyment. It also found "LSD is not physically addictive."

Despite doses as high as 2,400 micrograms per hundred pounds of body weight, only seven volunteers reported aftereffects, he said, because their selection was carefully controlled and "it was a lot different from the civilian drug culture." ("Army says LSD not dangerous", 1975)

What did the Army discover in its research on LSD?

The Army studies used healthy, young subjects; they used a pure form of the drug; the subjects took the drug in an atmosphere of social approval, with medical experts on hand. All this makes it hard to compare the Army results with unsupervised recreational use of the same drug.

Federal research money for investigating LSD and other psychedelics ceased to be available in 1975 just as the Army and CIA research became public. There was still great interest in using LSD as a psychiatric tool, but after the 1970s little research was done on the drug.

LSD was re-classified at that time as a Schedule 1 drug, a classi­fication reserved for the most dangerous substances. This made it difficult for researchers to obtain permission to do research on LSD.

That is slowly changing, and research on psychedelics is resuming. R. R. Griffiths of the Johns Hopkins Medical School, a Professor in the departments of Psychiatry and Neuroscience, heads the Psilocybin Research Initiative.

Griffith and his co-workers have tested psilocybin in double-blind controlled studies. They showed that a single psilocybin session gave subjects "mystical experiences" associated with positive changes in behaviors, attitudes and values more than a year later.

Other researchers reported positive effects of psilocybin in terminally ill cancer patients. A single "trip" provided many with lasting relief of existential dread.


"Army says LSD not dangerous" (1975, July 31) Ann Arbor News, p.1.

Hofmann, A. (1983). LSD, my problem child: Reflections on sacred drugs, mysticism, and science. Los Angeles: J.P. Tarcher.

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