Fifteen years on: evolving ideas in researching sex differences in depression

BACKGROUND: A cohort study of a socially homogeneous group of teachers was commenced in 1978 to pursue possible risk factors contributing to the recognized female preponderance of depression. METHODS: Multiple measures of depressive experience included: (i) lifetime rates, duration and number of depressive episodes using two caseness definitions, DSM-III-R major depression and 'all depression' (which included a category of minor depression); (ii) self-report measures of state and trait depression, neuroticism, and self-esteem. DSM-III-R anxiety disorder rates are also reported and co-morbidity with major depression examined. RESULTS: At the 15-year review in 1993, the sample had a mean age of 39 years, there was a trend for a female preponderance in lifetime rates of major depression and 'all depression' (and which was more pronounced with the inclusion of data for anxiety disorders), with statistically significant differences in rates of social and simple phobias and combined anxiety disorders. Mean neuroticism scores were consistently higher for women. CONCLUSIONS: The strong association between anxiety and depressive disorders suggests that greater reporting of anxiety and higher neuroticism scores in women may be a key determinant that contributes to any female preponderance in depression rates.