Sex differences in lifetime depression rates: fact or artefact?

To isolate determinants of any female preponderance in depressive disorder, we earlier selected a sample of young adults, then similar in terms of several potential social determinants of depression and with equivalent rates of lifetime depression. We now report a 10-year review, which initially suggested a female preponderance in DIS-generated RDC and DSM-III lifetime depressive categories. The presence of sex differences in rates of lifetime depression was influenced by the definition of caseness used and the vantage point from which rates were determined. The longitudinal design and earlier corroborative witness reports established, however, clear evidence of instability in prevalence estimates, together with a sex effect on stability. Men were more likely to 'forget' episodes, while women were more likely to 'remember' episodes that had generally not previously reached 'case' criteria. When correction was made for such artefactual influences, a sex difference in lifetime depression rates was no longer evident. Such findings require review in general community samples, and suggest modifications to 'case' definition in epidemiological enquiries.