The Zurich Study. XII. Sex differences in depression. Evidence from longitudinal epidemiological data.

A prospective study of depressive syndromes and diagnoses was performed among a young adult Swiss population with three interviews over 7 years. Different definitions of depressive states were used: on the one hand, depressive syndromes including mood disturbances of any severity, on the other, well-defined diagnoses of depression. Women were consistently overrepresented among subjects with depressive syndromes of some length and among those with DSM-III major depressive disorder. Both sexes appeared equally affected by brief recurrent depressions with work impairment. Between the ages of 20 and 30 years, men as a group in contradistinction to women showed depressive syndromes with decreasing frequency, whereas, for diagnoses, the sex rates remained quite constant. For identical syndromes, women at each interview reported a greater number of symptoms. DSM-III-R symptoms of melancholia were not reported more often by women than by men. When syndromes or diagnoses were controlled, women and men suffered to an equal rate from subjective impairment at work. Women's syndromes were more recurrent. Among women, a diagnosis of depression was more often associated with disturbances of appetite and with phobias than among men. The importance of differential recall for sex differences in prevalence is discussed. Sex differences may have different weight and different causes with regard to depressive syndromes and to a diagnosis of depression.