The epidemiology of affective disorders: national secular trends and local findings

Abstract

SummaryThis paper examines aspects of the epidemiology of affective disorders in Scotland. Results from 3 investigations are described, each one indicative of a particular research approach (the use of national, case-register and direct-interview based data). In Part I of the paper secular trends in Scottish national and local (Edinburgh city) first admission rates of affective disorders, based upon ICD-9, are examined. The results, based upon the national data, show that during the last two decades the male admission rate declined by 29.4% and the female rate by 37.3%. However, the female rate has remained 1.8 to 2.2-fold that of the male rate throughout this period. Further investigation of these changes was undertaken after dividing the affective disorder category into either the “affective psychoses” or the “depressive neuroses”. Results revealed that whilst there was only a slight change in the Scottish national rate of affective psychoses, marked decreases in rates were revealed for the depressive neuroses for both sexes (males by 39.4% and females by 39.3%). Age-specific secular trends also demonstrated the extent to which the older age groups of both sexes experienced the highest rates of affective psychoses.Results based upon first admissions for affective disorder to the Royal Edinburgh Hospital over the years 1976-1987 showed that the overall male rate had remained relatively unchanged, whilst that for females had declined by about 24%. Subsequent analysis showed that the rates for affective psychoses had declined over the 12 years to a level which for the females was close to the national rate but that the male rate for these conditions had remained (in 1985) at 70% above the Scottish national rate.Part II of this paper presents results from two further studies concerned with investigating rates of affective disorder amongst women. The first of these was a general population survey of a random sample, the second a hospital study. Both studies were designed to be complementary, in that each was based upon samples of women living in the same geographical area of Edinburgh city. Results revealed that the hospital prevalence estimate for affective disorders was only about 1% of the community estimate, but over 5% of the community inception rate. Analyses examining the demographic correlates of affective disorders revealed the extent to which age and marital status differentially determined the ease with which women entered hospital care. Results revealed that being single and of older age was associated with an increased chance of receiving treatment for women with affective disorders.