A drug or other substance that is capable of producing hallucinationsAlthough hallucinogenic chemicals have been utilized for both experimental and therapeutic purposes in Western psychiatry only since World War II, roots, seeds, and fungi with hallucinogenic properties were known to the ancient world and have long been used in tribal societies. Some of the potions employed in medieval witchcraft contained ingredients that may also be hallucinogenic—for instance, henbane, belladonna, toadskin, and the urine of certain animals.During the conquest of Central and South America, a number of powerful hallucinogenic substances came to light. The Peruvian Aztecs consumed the “divine” peyot, or peyote, made from dried cactus tops, or “buttons,” a natural source of the drug mescaline. Mexican Indians were using more than thirteen different “phantastica” (the botanical name for hallucinatory plants), including sacred mushrooms containing psilocybin, and olilinqui, the Indian name for morning glory. Other Indians in the Amazon basin ate hallucinogenic seeds known as cohoba, and drank caapi, which contained the drug harmine. Explorers also found tribes in the Congo who chewed tabernanthe iboga (ibogaine), inhabitants of Northern Siberia who ate a vision-inducing fungus called fly agaric, and natives of the Pacific Ocean who consumed a mullet known as the “dream fish.”All these drugs were apparently taken to induce fantastic visions and open the “doors of perception,” to use WilliamBlake’s expression. In some cases, the experience served ceremonial purposes; in others it provided release for deep- seated impulses or relief from oppressive situations. An early account of mushroom-eating, written by Bernardino de Sahagun, who lived among Mexican Indians from 1529 to 1590, shows how much the effects vary from individual to individual, probably reflecting the emotional needs and urges of different personalities: “The mushrooms they ate with honey, and when they began to get heated from them, they began to dance and some sang and some wept, for now they were drunk from the mushrooms. And some cared not to sing but to sit down in their rooms and stay there pensivelike and some saw in a vision that some wild beast was eating them, others saw in a vision that they were taken captives in war, others saw in a vision that they were to be rich, others saw in a vision that they were to own many slaves, others saw in a vision that they were to commit adultery and that their heads were to be bashed in therefore. . . . Then when the drunkenness of the mushrooms passed, they spoke with one another about the visions they had seen.” Mescaline, the hallucinogenic ingredient of the cactus plant, was isolated in 1888, and a short time later Weir Mitchell and Havelock Ellis began experimenting with it. The observations of these and other investigators indicate that the subjects experience (1) distorted perception of time, space, ordinary objects, and their own body image; (2) vivid visual illusions and hallucinations; (3) transformation of everyday things into objects of irridescent beauty; (4) a sense of detachment from all cares and concerns; (5) some degree of intellectual impairment, confusion, and clouded consciousness; (6) paranoid thinking and lack of emotional control;(7) the experience of “double consciousness”—that is, simultaneous awarenessof events in both the inner and outer worlds. See MITCHELL.The term psychedelic has recently been applied to mescaline and other hallucinogenic drugs, such as lysergic acid (LSD) and dimethyltriptamine (DMT), to denote their ability to stimulate the mind and expand perceptual experience. A second term, psychotomimetic, is also used since they produce psychosis-like reactions. However, studies show that they do not reproduce the exact manifestations of naturally occurring psychoses of either the functional or the organic type. Although they produce visual hallucinations, which are common in toxic psychoses, they do not usually produce the gross impairment of memory and orientation that occurs in brain syndromes due to lead poisoning, alcohol, barbiturates, and infectious diseases. Many of the symptoms resemble those found in acute schizophrenia—especially perceptual distortions, paranoid thinking, and visual hallucinations. On the other hand, they do not produce auditory hallucinations, which are frequently observed in schizophrenia. And even though verbal and affective changes may be induced, they are quite different from those occurring in natural forms of schizophrenia. The experimental subject tends to become emotionally excited and talk wildly; the true schizophrenic is more likely to retreat into silence, to use garbled verbiage, and to be emotionally flat and unresponsive.In spite of these differences, mescaline has been investigated as a possible key to schizophrenia. A number of researchers have suggested that schizophrenic reactions might be associated with malfunction of the adrenal gland, and in 1952 Osmond and Smythies noted similarities between the chemical structure of mescaline and that of epinephrine (adrenalin). This prompted a search for components of epinephrine or substances related to it that would be capable of producing the same symptoms as schizophrenia. A number of such substances, including adrenoxin, were found to induce temporary psychotic states, but none of them has been conclusively proved to be present in higher than normal amounts in natural forms of schizophrenia. However, even though the experimental studies on mescaline have not demonstrated that toxic substances are involved in schizophrenia, the search continues and has recently focused on another hallucinogenic drug, LSD-25. See LYSERGIC ACID.In the following excerpts, compare the reactions of Weir Mitchell to mescaline with the visions experienced by the poet George William Russell (AE) without the use of a drug.