Delta sleep EEG in depressed adolescent females and healthy controls.

Background: Quantitative EEG studies have identified a number of sleep abnormalities in adults with major depressive disorders (MDD), including a reduction in the amplitude of delta activity during NREM sleep. To date, these methodologies have not been used in early onset MDD.
Methods: Delta activity during NREM sleep was compared in eight symptomatic but unmedicated adolescent females with MDD and eight age- and gender-matched healthy controls.
Results: The depressed group showed significantly lower delta amplitude and power in the first NREM sleep period. By contrast, standard sleep architecture did not differentiate between groups.
Limitations: Given the sample size, this study is best viewed as tentative. In addition, it has yet to be determined whether adolescent males with MDD also show delta sleep abnormalities. Further, failure to find between-group differences in REM latency or other macroarchitectural measures may be due to the small sample size.
Conclusions: The findings of this study underscore the utility of quantitative sleep EEG techniques in early onset MDD. The results of the present study do, however, diverge from reports in adults with MDD, where delta abnormalities are more prevalent in men. Such findings suggest that the maturational time course of sleep EEG disturbances may differ for males and females with depression. Early emergence of delta abnormalities in depression may be of relevance to clinical course of illness.