Sex differences in unipolar depression: Evidence and theory.

Abstract

A large body of evidence indicates that women are more likely than men to show unipolar depression. Five classes of explanations for these sex differences are examined and the evidence for each class is reviewed. Not one of these explanations adequately accounts for the magnitude of the sex differences in depression. Finally, a response set explanation for the sex differences in depression is proposed. According to this explanation, men are more likely to engage in distracting behaviors that dampen their mood when depressed, but women are more likely to amplify their moods by ruminating about their depressed states and the possible causes of these states. Regardless of the initial source of a depressive episode (i.e., biological or psychological) men's more active responses to their negative moods may be more adaptive on average than women's less active, more ruminative responses. The epidemiology of a disorder can provide important clues to its etiology. When a disorder only strikes persons from one geographical region, one social class, or one gender, we can ask what characteristics of the vulnerable group might be making its members vulnerable. A frequent finding in epidemiological studies of mental disorders is that women are more prone to unipolar affective disorders than are men (Boyd & Weissman, 1981; Weissman & Klerman, 1977). A number of different explanations have been proposed to account for women's greater vulnerability to depression. Previous reviews of these explanations (e.g., Weissman & Klerman, 1977) have been quite brief and uncritical. In this article, the evidence for sex differences in unipolar depression first is summarized, then the most prominent explanations proposed for these sex differences are discussed in detail. These explanations include those attributing the differences to the response biases of subjects, as well as biological, psychoanalytic, sex role, and learned helplessness explanations. Although most of the proposed explanations for sex differences in depression have received some empirical support, not one of them has been definitively supported and not one as yet accounts for the magnitude of sex differences in depression. In the final section of this article it is suggested that differences in the ways that men and women respond to their own depressive episodes, whatever the origin of these episodes, may be an important source of the sex differences observed in depression.

Volumetric Analysis of the Prefrontal Cortex, Amygdala, and Hippocampus in Major Depression

“…Major depressive disorder (MDD) affects 13-14 million American adults each year (Kessler et al, 2003), with an annual prevalence of 12% in women compared with 7% for males (Nolen-Hoeksema, 1987). In addition, 21% of women will have an episode of major depression in their lifetime compared with 13% in males (Kessler et al, 1994).…”

Estrogen-mediated effects on depression and memory formation in females

“…One of the more striking features of depression is the fact that twice as many females experience some form of depression when compared to males (Earls, 1987). In addition to increased incidence, their depressive episodes can last longer, be more severe and often recur (Nolen-Hoeksema, 1987). It is recognized that some environmental and sociocultural factors contribute to the sex difference in depression.…”

“…As such, they are often times diagnosed as substance abusers or antisocial rather than depressive. Also, females often appear more depressed because they tend to ruminate more about their mood (Nolen-Hoeksema, 1987). Finally, the changing role of women in the workplace seems to contribute to the sex difference.…”

Effects of responses to depression on the remediation of depressive affect.

“…The response styles theory of depression (Nolen-Hoeksema, 1987) proposes that individuals who engage in ruminative responses to depressed mood will experience amplification and prolongation of the mood, whereas individuals who engage in distracting responses to their depressed mood will experience relief from that mood. Ruminative responses are cognitions…”

“…On the basis of Nolen-Hoeksema's (1987) response styles theory of depression, it was hypothesized that distracting, active responses would be more effective in alleviating a depressed mood than would ruminative, passive responses. A depressed mood was induced in 35 male and 34 female Ss, and subjects were randomly assigned to engage in 1 of 4 types of responses: an active task that distracted them from their mood; a passive, distracting task; an active task designed to lead to ruminations about their mood; or a passive, ruminative task.…”