The association between mild geriatric depression and reproductive history--a Darwinian approach

The well described trend of population ageing results in a dramatic increase in the number of elderly, reporting symptoms of depression, the most common mood disorder today. Various intrinsic and extrinsic factors are discussed to be responsible for this increase of mood disorders. In the present study the association patterns between mild geriatric depression and the individual reproductive history are analyzed. 264 subjects, 167 females and 97 males, ageing between 60 and 95 years (mean 72.3, SD 8.1 yrs) were enrolled in the present study. The prevalence of depression was tested by mean of the geriatric depression scale (GDS), additionally reproductive history was documented. It turned out, that with increasing number of offspring the depression score decreased. Childless women exhibited the highest prevalence of mild depression and the highest mean depression score. These association patterns between reproductive history and depressive disorders during old age were discussed by means of Darwinian psychiatry. A low number of offspring or childlessness and a lack of social networks for support are new in the evolutionary history of Homo sapiens. Mild geriatric depression may be interpreted as a result of a mismatch or dysregulation because the recent social environment of elderly is completely different from that in which Homo sapiens evolved. The occurrence of geriatric depression may be an adaptation to this new situation.