Burden of disease. Methods of calculating disability from mental disorder

Background: The Global Burden of Disease studies are important because they encompass morbidity as well as mortality. Burden due to morbidity is calculated from incidence, duration and disability. There is a dearth of epidemiological measurements of disability.

Method: Data from a quasi-community sample (n=1364) were analysed. Diagnoses of mental and physical disorders, and reports of disability, were based on established methods.

Results: The disabilities reported in mental and physical disorders were comparable. Disability was correlated with comorbidity. The disability in mental disorders was examined by three methods: pure disorders, main problem and regression. It appears that major depression and substance disorder weights were overestimated, and anxiety disorder weights were underestimated in the Global Burden of Disease studies.

Conclusions: A method for disentangling the effects of concurrent comorbidity is presented. The size of burden attributed to mental disorders is of potential benefit for funding mental health services. It is important that we get the estimates right.