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May 1956

Lysergic Acid Diethylamide in Patients with Excess Serotonin

Author Affiliations

Bethesda, Md.

From the National Institutes of Health, National Heart Institute, and the National Institute of Mental Health, U. S. Public Health Service, Department of Health, Education, and Welfare.

AMA Arch NeurPsych. 1956;75(5):488-492. doi:10.1001/archneurpsyc.1956.02330230038003

In contrast to other lysergic acid derivatives, lysergic acid diethylamide (LSD) is an extremely potent "hallucinogenic" agent.* Considerable attention has been given to Gaddum's suggestion that the psychological effects of LSD might be due to an antagonism of 5-hydroxytryptamine (serotonin) in brain. This amine is present in the central nervous system with particular localization in the hypothalamus, mesencephalon, and medulla.† The observation that LSD is antagonistic to the stimulant effects of serotonin on various types of smooth muscle in vitro5 led Gaddum to speculate that "it is possible that the H-T (serotonin) in our brains plays an essential part in keeping us sane and that the effect of LSD is due to its inhibitory action on the H-T in the brain."6 A similar notion was expressed by Woolley and Shaw,7 who found that harmine, a potent hallucinogen,8 is also a serotonin antagonist. The observation of Shore,

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