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.

Sex differences in unipolar depression: evidence and theory.

• Using positron emission tomography, we studied cerebral glucose metabolism in drug-free, age- and sex-matched, righthanded patients with unipolar depression (n =10), bipolar depression (n =10), obsessive-compulsive disorder (OCD) with secondary depression (n =10), OCD without major depression (n =14), and normal controls (n =12). Depressed patients were matched for depression on the Hamilton Depression Rating Scale, and subjects with OCD without depression and OCD with depression had similar levels of OCD pathology. We also studied six non—sex-matched patients with mania. Mean ( ± SD) glucose metabolic rates for the left dorsal anterolateral prefrontal cortex, divided by the rate for the ipsilateral hemisphere as a whole (ALPFC/hem), were similar in the primary depressions (unipolar depression = 1.05 ±0.05; bipolar depression =1.04 ± 0.05), and were significantly lower than those in normal controls (1.12 ± 0.06) or OCD without depression (1.15 ± 0.05). Results for the right hemisphere were similar. Values in subjects with OCD with depression (1.10 0.05) were also significantly lower than in subjects with OCD without depression, and values in subjects with bipolar depression were lower than those in manic subjects (1.12 ± on this measure in the left hemisphere, although results were not significant in the right hemisphere. There was a significant correlation between the HAM-D score and the left ALPFC/hem. With medication for depression (n =12), the left ALPFC/hem increased significantly and the percentage change in the Hamilton scale score correlated with the percentage change in the left ALPFC/hem. These data support other findings that major depression is associated with a left ALPFC abnormality.

Reduction of prefrontal cortex glucose metabolism common to three types of depression.

Data from the Epidemiologic Catchment Area survey were used to examine the relationship between violence and psychiatric disorders among adults living in the community. Psychiatric assessment of survey respondents was based on the Diagnostic Interview Schedule, which also provided self-report information about violent behavior. Those who reported violent behavior within the preceding year tended to be young, male, and of low socioeconomic status, and more than half met DSM-III criteria for one or more psychiatric disorders. Subjects with alcohol or drug use disorders were more than twice as likely as those with schizophrenia to report violent behavior. In a multivariate model of the predictors of violence, a significant interaction effect was found between major mental illness and substance abuse. The risk of violent behavior increased with the number of psychiatric diagnoses for which respondents met DSM-III criteria.

Violence and Psychiatric Disorder in the Community: Evidence From the Epidemiologic Catchment Area Surveys

Objective
To assess whether patients receiving aerobic exercise training performed either at home or in a supervised group setting achieve reductions in depression comparable to standard antidepressant medication (sertraline) and greater reductions in depression compared to placebo controls.

/pdf/exercise-and-pharmacotherapy-in-the-treatment-of-major-1cttv4djx7.pdf

Exercise and pharmacotherapy in the treatment of major depressive disorder

Cerebral metabolic rates for glucose were examined in patients with unipolar depression (N = 11), bipolar depression (N = 5), mania (N = 5), bipolar mixed states (N = 3), and in normal controls (N = 9) using positron emission tomography and fluorodeoxyglucose F 18. All subjects were studied supine under ambient room conditions with eyes open. Bipolar depressed and mixed patients had supratentorial whole brain glucose metabolic rates that were significantly lower than those of the other comparison groups. The whole brain metabolic rates for patients with bipolar depression increased going from depression or a mixed state to a euthymic or manic state. Patients with unipolar depression showed a significantly lower ratio of the metabolic rate of the caudate nucleus, divided by that of the hemisphere as a whole, when compared with normal controls and patients with bipolar depression.

https://jamanetwork.com/journals/PSYCH/articlepdf/493564/archpsyc_42_5_002.pdf

Cerebral metabolic rates for glucose in mood disorders. Studies with positron emission tomography and fluorodeoxyglucose F 18.

Onset of response in relation to outcome in depressed outpatients with placebo and imipramine.

Search for biological/genetic markers in a long-term epidemiological and morbid risk study of affective disorders

Violence to self and to others on a locked, acute-care unit is reported for a three-year period. Drug abuse correlated strongly with both types of violence. Self-violence appeared to be a more predictable event due to its diagnostic specificity, history of prior violence and timing of the episodes. Assaults occurred more randomly demonstrating only a mild association with schizophrenia, but not with other psychotic disorders.

David L. Dunner

Papers

Onset of response in relation to outcome in depressed outpatients with placebo and imipramine.

Search for biological/genetic markers in a long-term epidemiological and morbid risk study of affective disorders

Self and other directed violence on a closed acute-care ward

Platelet MAO-B activity in anxiety and depression.

Rapid Cycling Bipolar Manic Depressive Illness