Sleep deprivation in depression: pattern of relapse and characteristics of preceding sleep.

The pattern of relapse following therapeutic response to 40-hr sleep deprivation (SD) was examined in nine depressed patients. On the night ending SD patients were awakened from polygraphically recorded sleep on one or more occasions, in order to assess the clinical state. All subjects were found to demonstrate a precipitous and full relapse over this night, the timing of the relapse varying considerably between individuals. No association was found between deterioration in the clinical state and characteristics of preceding sleep. These results are consistent with the notion that, in predisposed individuals, some process associated with sleep has a depressogenic effect. However, they necessitate revision of theories of SD and depression that emphasize the infrastructure of sleep.