ELECTROENCEPHALOGRAPHIC SLEEP PROFILES BEFORE AND AFTER COGNITIVE-BEHAVIOR THERAPY OF DEPRESSION

Background: Previous studies have not fully resolved the state-depende nt vs traitlike behavior of the electroencephalographic sleep abnormal ities associated with depression. We therefore examined the sleep prof iles of depressed patients before and after 16 weeks of treatment with cognitive behavior therapy to determine the stability or reversibilit y of selected abnormalities. Methods: Seventy-eight unmedicated patien ts with major depressive disorder were stratified into abnormal and no rmal subgroups on the basis of pretreatment sleep study results. Two p rospectively defined types of sleep variables were studied: those expe cted to be traitlike or state independent (type 1) and those predicted to be reversible or state dependent (type 2). Results: The type 1 sle ep disturbances (reduced rapid eye movement latency, decreased delta s leep ratio, and decreased slow wave sleep [in percentage]) were stable , as predicted, across time. A composite measure of type 2 disturbance s (based on rapid eye movement latency, sleep efficiency, and rapid ey e movement density) improved significantly, although a minority of pat ients in remission had persistent abnormalities. Conclusions: The elec troencephalographic sleep correlates of depression can be disaggregate d into state-independent and partially reversible subgroups. Persisten t sleep disturbances in remitted patients may have ominous prognostic implications.