Gender differences in depression: a study of older unlike-sex twins.

Gender differences in depressive symptoms, in the diagnosis of major/minor depression, and in the use of antidepressant medication were investigated. The sample included 249 pairs of unlike-sex twins, who were between 70 and 80 years of age at the initial, baseline assessment. A follow-up, in which both members of 145 twin pairs participated, was carried out four years later. Participants completed the Centre for the Epidemiologic Studies Depression Scale (CES-D) for depressive symptoms. Current use of antidepressant medicine was assessed. Medical records of major/minor depression from the period 1985-1998, including a summary of those diagnoses in earlier years, were gathered from several sources. Women had a higher frequency of depressive symptoms and depression diagnoses than their twin brothers. Depressive symptoms and diagnosis of depression increased over time, slightly more among men. The gender difference and increase over time in the depressive symptoms were related to differences in socio-economic status and physical functioning in men and women. No gender difference was found in the use of antidepressant medication.