The excess cost of depression in South Australia: a population-based study

Objective: To establish excess costs associated with depression in South Australia, based on the prevalence of depression (from the Primary Care Evaluation of Mental Disorders (PRIME-MD)) and associated excess burden of depression (BoD) costs. Method: Using data from the 1988 South Australian (SA) Health Omnibus Survey, a properly weighted cross-sectional survey of SA adults, we calculated excess costs using two methods. First, we estimated the excess cost based on health service provision and loss of productivity. Second, we estimated it from loss of utility. Results: We found symptoms of major depression in 7% of the SA population, and 11% for other depression. Those with major depression reported worse health status, took more time off work, reported more work performance limitations, made greater use of health services and reported poorer health-related quality-of-life. Using the service provision perspective excess BoD costs were AUD$1921 million per annum. Importantly, this excluded non-health service and other social costs (e.g. family breakdown, legal costs). With the utility approach, using the Assessment of Quality of Life (AQoL) instrument and a very modest life-value (AUD$50 000), the estimate was AUD$2800 million. This reflects a societal perspective of the value of illness, hence there is no particular reason the two different methods should agree as they provide different kinds of information. Both methods suggest estimating the excess BoD from the direct service provision perspective is too restrictive, and that indirect and societal costs ought be taken into account. Conclusions: Despite the high ranking of depression as a major health problem, it is often unrecognized and undertreated. The findings mandate action to explore ways of reducing the BoD borne by individuals, those affected by their illness, the health system and society generally. Given the limited information on the cost-effectiveness of different treatments, it would seem important that resources be allocated to evaluating alternative depression treatments.