MIND, BRAIN AND BIOCHEMISTRY 401 



and barbiturates." Ethyl alcohol, as everyone knows, affects 

 normal behavior in varying degrees. In extreme alcoholism, as 

 for example in delirium tremens and acute alcohol hallucinosis, 

 optic and auditory hallucinations, respectively, are common.*^ 



A very interesting group recently brought to the attention 

 of the psychiatric profession is known as psychomimetic drugs. 

 A descriptive definition of these drugs presented a few years 

 ago is still adequate: " Psychomimetic agents are substances 

 that produce changes in thought, perception, mood, and, some- 

 times, in posture, occurring alone or in concert, without causing 

 either major disturbances of the autonomic nervous system or 

 addictive craving, and, although with overdosage, disorienta- 

 tion, memory disturbance, stupor and even narcosis may occur, 

 these reactions are not characteristic." *' In some respects the 

 behavioral changes brought about by these drugs resemble the 

 mental and emotional symptoms associated with one or other 

 of the psychoses. Most of these drugs in current experimental 

 use are naturally occurring compounds, or compounds obtained 

 from them by slight chemical change. Among the better known 

 of these interesting drugs are lysergic acid diethylamide (LSD- 

 25) , mescaline (from the Peyote cactus) , and psilocybin (from 

 the mushroom, Psilocybe mexicana Heim) . 



The first of these drugs, LSD-25, is apparently unique in the 

 truly minute amount which will produce the typical mental 

 changes. These changes usually begin in an half hour and reach 

 a peak at one and one-half hours. Among the outstanding 

 symptoms are visual hallucinations, often fantastic in structure. 

 While auditory hallucinations are rare, taste disturbances are 

 quite frequent. Consciousness itself, however, is never markedly 

 affected, and orientation in place remains intact, but there is 

 rather a profound change in the perception of time. After about 



*" M. Levin, " Toxic Psychoses," ed. cit., p. 1225 ff. 



*^ G. N. Thompson, "Acute and Chronic Alcoholic Conditions," in S. Arieti, op. 

 cit., pp. 1208-1210. 



** H. Osmond, "A Review of the Clinical Effects of Psychomimetic Agents," 

 Annals of the New York Acadeviy of Science, LXVI (1957), 418. 



