Contributor: Travis Barlock MD Educational Pearls: Alcohol binds the GABA receptor, which produces an inhibitory response, hence the “depressive” effects of ethanol beverages. Over time, alcohol downregulates the GABA receptors, leading to unopposed glutamate activity. Given that glutamate is excitatory, this can lead to seizures. Alcohol also suppresses REM sleep; in patients with chronically suppressed REM sleep, the brain starves for dream sleep and it spills over into the wakeful state, inducing a dream-like state when someone is awake. The awake dream-like state of delirium tremens (DT) differs from alcohol hallucinosis Alcohol hallucinosis presents with visual hallucinations in a wakeful state DT presents with a generalized clouding of the sensorium and a dream-like state Treatment for DT is better achieved with phenobarbital due to predictable pharmacology Phenobarbital acts on GABA and NMDA receptors References 1. Davies M. The role of GABAA receptors in mediating the effects of alcohol in the central nervous system. J Psychiatry Neurosci. 2003;28(4):263-274. 2. Fujimoto J, Lou JJ, Pessegueiro AM. Use of Phenobarbital in Delirium Tremens. J Investig Med High Impact Case Reports. 2017;5(4):4-6. doi:10.1177/2324709617742166 3. Walker, M. Chapter 13: iPads, Factory Whistles, and Nightcaps In: Walker, M, Why We Sleep. Scribner; 2017, pg. 272.  4. Zarcone V. Alcoholism and sleep. Adv Biosci. 1978;21:29-38. Summarized & Edited by Jorge Chalit, OMSII