Social factors and the psychobiology of depression: Relations between life stress and rapid eye movement sleep latency.

Abstract

We examined psychosocial factors (i.e., life stress) and biological factors (i.e., REM sleep latency) that are hypothesized to be of complementary importance for defining depressive subtypes in a sample of 61 nonpsychotic, endogenous major depressives. Subjects were evaluated on several diagnostic scales for life stress, on electroencephalographic sleep data, and on 2 symptom measures for depression. As predicted, persons with severe stress that occurred shortly before depression onset had essentially normal REM latency values; patients without such stress had reduced REM latency values. Both stress and REM latency were also associated with greater severity of self-reported depressive symptoms. Alternative explanations of these findings are discussed, with particular emphasis on different roles of pre-onset and post-onset stressors.