Specific culture-related features are discussed in the text for Major Depressive Episode. Epidemiological studies suggest significant cohort effects in risk of depression. For example, individuals born between 1940 and 1950 appear to have an earlier age at onset and a greater lifetime risk of depression than those born prior to 1940. There is some evidence that Atypical Features are more common in younger people and that Melancholic Features are more common in older depressed people. Among those with an onset of depression in later life, there is evidence of subcortical white matter hyperintensities associated with cerebrovascular disease. These “vascular” depressions are associated with greater neuropsychological impairments and poorer responses to standard therapies. Major Depressive Disorder (Single or Recurrent) is twice as common in adolescent and adult females as in adolescent and adult males. In prepubertal children, boys and girls are equally affected.
Studies of Major Depressive Disorder have reported a wide range of values for the proportion of the adult population with the disorder. The lifetime risk for Major Depressive Disorder in community samples has varied from 10% to 25% for women and from 5% to 12% for men. The point prevalence of Major Depressive Disorder in adults in community samples has varied from 5% to 9% for women and from 2% to 3% for men. The prevalence rates for Major Depressive Disorder appear to be unrelated to ethnicity, education, income, or marital status.