Although spousal bereavement in late life is common and frequently leads to major depression, the boundary between bereavement without a depressive syndrome and bereavement-related depression has been insufficiently studied from a physiological perspective. Because other forms of depression are associated with physiological changes, including sleep, we have attempted to clarify the relationship of bereavement and bereavement-related depression by investigating electroencephalographic (EEG) sleep in 31 elderly volunteers with recent spousal bereavement, stratified by the presence (n = 15) or the absence (n = 16) of major depression (Research Diagnostic Criteria). Entry into the study was limited to volunteers without a personal history of psychiatric disorder. As hypothesized, bereaved subjects with major depression had significantly lower sleep efficiency, more early morning awakening, shorter rapid eye movement (REM) latency, greater REM sleep percent, and lower rates of delta wave generation in the first nonREM (NREM) period, compared with bereaved subjects without depression. Furthermore, the sleep of bereaved subjects with single-episode major depression resembled that of elderly patients with recurrent unipolar major depression (n = 15) on measures noted above. Sleep in bereavement without depression was similar to that of 15 healthy control subjects (neither bereaved nor depressed). These findings suggest that the current DSM-III-R concept of uncomplicated bereavement is not confirmed, as the sleep patterns of subjects who develop a depressive syndrome in the context of bereavement, many of whom might be considered to have "uncomplicated bereavement" by DSM-III-R standards, are identical to sleep patterns found in major depressive episodes. To our knowledge, this is the first study of EEG sleep in spousal bereavement with and without major depression.