Total and partial sleep deprivation in clomipramine-treated endogenous depressives.

Improvement in depression after total sleep deprivation (TSD) is, as a rule, followed by relapse after subsequent ad libitum sleep. This study is addressed to the question of how nocturnal partial sleep following TSD affects this relapse. Thirty endogenously depressed patients participated in the study. During the night after TSD, subjects were allowed sleep during one of three periods, i.e., unlimited sleep (11:00 p.m.-8:00 a.m.), early partial sleep (11:00 p.m.-3:00 a.m.), or late partial sleep (4:00 a.m.-8:00 a.m.). The hypothesis that partial sleep deprivation on the night following TSD prevents relapse has to be rejected. Relapse was inversely related to a drop in minimum rectal temperature during the night with unlimited or partial sleep, compared with minimum rectal temperature on the previous night.