The aetiology of depression.

This review will start by considering studies of the genetic contribution to the liability to depression, and go on to consider some of the ways in which environmental factors can modify gene expression. This will lead on to the pathways by which the genetic factors also appear to control stressful life events in adolescence and adult life, and then to a consideration of causes that are entirely environmental. We will conclude by considering the causes of the gender differences in the prevalence of depression during adult life.