166 Depressive Disorders
Despite consistent differences between gender s in prevalence rates for depressive disor-
ders, there appear to be no clear differences by gender in phenomenology, course, or treat-
ment response. Similarly, there are no clear effe cts of current age on the course or treatment
response of major depressive disorder. Some symptom differe nces exist, though, such that
hypersomnia and hyperphagia ar e more likely in younger individuals, and melancholic
symptoms, particularly psychomotor disturbances, are more common in older individuals.
The likelihood of suicide attempts lessens in mi ddle and late life, although the risk of com-
pleted suicide does not. Depressions with ea rlier ages at onset are more familial and more
likely to involve personality disturbances. The course of major depressive disorder within
individuals does not generally change with aging. Mean times to recovery appear to be sta-
ble over long periods, and the likelihood of be ing in an episode does not generally increase
or decrease with time. 
Risk and Prognostic Factors
Temperamental. Neuroticism (negative affectivity) is a well-established risk factor for the
onset of major depressive disorder, and high le vels appear to render individuals more likely
to develop depressive episodes in re sponse to stressful life events.
Environmental. Adverse childhood experiences, part icularly when there are multiple
experiences of diverse types, constitute a set of  potent risk factors for major depressive dis-
order. Stressful life events are well recognized  as precipitants of major depressive epi-
sodes, but the presence or absence of adverse life events near the onset of episodes does
not appear to provide a useful guide to prognosis or treatment selection.
Genetic and physiological. First-degree family members of individuals with major de-