Patterns of response to repeated total sleep deprivations in depression

Background: Patterns of response and nonresponse in repeated sleep deprivat ion (SD) are of both clinical and scientific interest, as yet, studies have yielded inconsistent results. Methods: 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 w ere under a constant antidepressant medication with amitriptyline. SD effec ts were measured using observer and self rating scales. Results: Each singl e 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 af ter the sixth TSD). The majority of patients exhibited a pattern of respons es and nonresponses randomly distributed over time. Ther e was no temporal trend. The initial effect did not predict the average response to the follo wing SDs. Limitations: One third of patients dropped out before completing the protocol which limits the scope of the study. Conclusions: Response to a single SD is not generalizable on a series of following SDs in an individ ual. Thr mechanism of action of SD does probably not involve mechanisms sub jected to habituation or sensitization. (C) 2001 Elsevier Science B.V. All rights reserved.