Aims: The aim of this study was to evaluate the impact of depression on quality of life in the general population by studying its effects on i) health-related quality of life (HRQoL), ii) health state utilities, and iii) the burden of disease in the population according to age, sex, marital status, education, economy and employment.
Method: Cross-sectional survey in the County of Uppsala, Sweden. A statistical sample of the general population aged 20-64 years (N=4506) was used. Information on current state of depression was obtained by self-report. HRQoL was measured using Short Form 36 (SF-36). The time trade-off (TTO) method was used to measure health state utilities. The decrease of total health state utilities associated with depression in the population was used as a measure of burden of disease.
Results: Depression was reported by 4.0% of the population. Those with depression scored significantly lower (P<0.001) than those without on all eight of the SF-36 domains. The depressed group also rated their health state utilities significantly lower than the others: 0.796 versus 0.933 (P<0.001). In the multivariate analysis of decrease in utilities with various medical disorders, depression was associated with the greatest decrease (-0.090, P<0.001). Persons with depression accounted for 10.9% of the total decrease in utilities in the whole population, but this proportion varied according to the specific subgroup. For example, 16.4% and 8.6% of the total burden of disease was linked to depression among single and married people, respectively. The corresponding figures for those with the lowest and highest incomes were 15.0% and 7.9%, respectively. Among the unemployed, persons reporting depression accounted for 15.3% of the decrease in utilities in contrast to 4.9% among the employed.
Conclusions: Depression has a strong impact on the quality of life and total disability in the general population. Further, the impact of depression is unevenly distributed in the population.