The European Study of the Epidemiology of Mental Disorders (ESEMeD) project: an epidemiological basis for informing mental health policies in Europe

Mental disorders are increasingly recognized as a major source of disability in the world. The costs associated with mood and anxiety disorders are very high. Forecasted future increase in the magnitude of mental disorders (1) will most likely be associated with higher costs. Nevertheless, population-based knowledge about the prevalence and distribution of mental disorders, their risk factors and their social and economic consequences is still limited. As is evidence about the efficiency of health services in managing the burden of these disorders. Whilst one would hope that our knowledge base will improve in the future it has to be noted that, for instance, the funding for depression research by the US National Institute of Health was significantly lower than might be expected based on the criterion of disability adjusted life years, when compared to 29 other conditions (2). The main sources of information about the prevalence and the burden of mental disorders diagnostic categories at the community level originated in work carried out in the United States. The Epidemiological Catchment Area (ECA) (3, 4) and the subsequent National Comorbidity Survey (NCS) (5) have provided key epidemiological data that have been used to estimate the burden of mental disorders everywhere. These seminal studies clearly showed that mood and anxiety disorders are frequent, and suggested that the level of unmet need for care is high. Similar findings have been reported in subsequent national studies (6, 7), but several studies have indicated that there may be substantial international variability in the prevalence of mental disorders (8, 9) as well as important differences in the provision and access to mental health care (9, 10). A number of previous population-based studies of mental disorders have been carried out in European countries, among these are the DEPRES study, carried out in six European countries (11), the NEMESIS study, in the Netherlands (12) the National Survey, in the UK (13), and the mental health supplement to the German National Health Interview and Examination Survey (14). Although they have provided valuable information on the epidemiology of mental disorders within Europe, each was conducted in one country or addressed a narrower scope of mental disorder, somewhat limiting their usefulness for informing health policy across Europe as a whole. The variation in the way European countries deliver their care to people with mental disorders is high. There are huge differences in personnel, settings, financing, as well as liaison with the wider health system across Europe (15). Several mental health policy reforms are ongoing on the continent. Successful policies must be based on valid and reliable knowledge of the relative efficiency of alternative organizational systems in order to reduce mental health disability. This knowledgebased approach is especially important for the emerging reality of the European Union, where economy, policy, and legislation, all of them affecting mental health care delivery, are called to converge in the near future.