Terminal sleep following delirium tremens in chronic alcoholics--polysomnographic and behavioral study

Delirium tremens frequently ends with behaviorally deep sleep after which the patient has usually recovered from the withdrawal state. This sleep has been called "terminal sleep" or "critical sleep". In the present study terminal sleep was investigated in 14 chronic alcoholics. Polysomnographic recordings were undertaken during terminal sleep and the patients' behavior was observed after the patients awoke from terminal sleep. A marked decrease in stages 3 and 4 sleep was found in all the patients. Sleep cycles were regularly observed in 10 patients, while in the remaining four patients sleep cycles were not observed in terminal sleep. The patients who exhibited regular sleep cycles had fully recovered from delirium tremens after they awoke from terminal sleep, and they never relapsed into delirium tremens afterwards. In contrast, the patients who demonstrated terminal sleep in which sleep cycles were not observed revealed inactive and sometimes disoriented behavior suggesting slight disturbances of consciousness. These patients developed delirium tremens repeatedly thereafter. Therefore, terminal sleep can be divided into two different types. One is recovery sleep from sleep deprivation induced by delirium tremens, in which sleep cycles are observed. The other is not sleep, but a state which is indicative of disturbances of consciousness.