Patterns of response to repeated total sleep deprivations in depression

Patterns of response and nonresponse in repeated sleep deprivation (SD) are of both clinical and scientific interest; as yet, studies have yielded inconsistent results.

Eighteen inpatients suffering from a major depression were subjected to a series of six scheduled total sleep deprivations within 3 weeks; 12 of them completed the whole protocol. All were under a constant antidepressant medication with amitriptyline. SD effects were measured using observer and self rating scales.

Each single SD led to a significant improvement. Of the 12 patients who completed the protocol, seven were classified as responders at endpoint (i.e., 1 week after the sixth TSD). The majority of patients exhibited a pattern of responses and nonresponses randomly distributed over time. There was no temporal trend. The initial effect did not predict the average response to the following SDs.

One third of patients dropped out before completing the protocol which limits the scope of the study.

Response to a single SD is not generalizable on a series of following SDs in an individual. The mechanism of action of SD does probably not involve mechanisms subjected to habituation or sensitization.