Five variations of sleep deprivation in a depressed woman.

Systematic variation in aspects of the sleep-wakefulness cycle of a depressed woman showed that recovery occurred reliably after 19 to 20 hours sustained wakefulness, unrelated to diurnal rhythm. Depression returned during as little as 15 minutes sleep. The effect of sleep deprivation was a specific response, probably unrelated to REM sleep. [ABSTRACT FROM AUTHOR]