Sex differences in the lifetime prevalence of depression: does varying the diagnostic criteria reduce the female/male ratio?

Most studies report the lifetime prevalence of major depressive disorder to be higher among women than men. One possible explanation is that this finding is the result of the diagnostic criteria used, in particular the inclusion of criterion symptoms associated with depressed mood. The number of criterion symptoms required for a diagnosis were varied and applied to 2163 first-degree relatives of affectively disordered probands of the NIMH Collaborative Study of the Psychobiology of Depression. Results indicated that differences between men and women in number of symptoms reported could not account for the difference in rates of depression. Women had a greater number of associated symptoms only at higher symptom levels, suggesting an excess of women only above a diagnostic threshold. Thus, findings supported a true difference in rates of major depressive disorder rather than a general trend for women to remember or report more criterion symptoms.