Editorials Depression: major problem for public health

The aim of this Editorial is to discuss depression as an important disorder for public health. The literature regarding epidemiology, consequences, adequacy of service delivery and prevention of depression is reviewed. Depression is a common disorder with high lifetime rates, particularly in women, and those experiencing social adversity. It is a major cause of disability, and causes death both by suicide and due to raised rates of physical disorders. Many cases are undiagnosed and treatment is often inadequate. Primary prevention is not yet easily feasible but secondary prevention by earlier recognition, public and professional education, can produce benefits. There is a need for public health programmes aimed at improving recognition, treatment, and reducing consequences. The public health approach to a disorder concerns its occurrence in populations. It encompasses consideration of its epidemiology; consequences; causes, especially those relevant to prevention; treatment, including delivery of services, access and outcome; prevention. Seen in this context depression emerges as a major problem: a common disorder, which produces much disability, impact on families and children, economic costs, load on services, death by suicide and from physical disorders. There are large deficiencies in recognition and treatment delivery which need to be addressed. In reviewing these issues European studies will be given particular attention. EPIDEMIOLOGY AND ASSOCIATED FACTORS The last quarter century has seen great activity in psychiatric epidemiology, with improved interview case finding methods leading to numerous large scale community surveys in many countries, and rates for disorder which are now fairly consistent and well established, at least for affluent Western countries. We have recently reviewed European studies of depression (Paykel et al, 2005a). For Address for correspondence: Professor E.S. Paykel, University of Cambridge, Department of Psychiatry, Douglas House, 18e Trumpington Road, Cambridge CB2 2AH (United Kingdom). Declaration of Interest: E.S. Paykel has received lecture honoraria and travel expenses in the last two years from drug companies with interests in antidepressants. Portions of this paper have been modified from Paykel et al. (2005a). 12 month prevalence, figures vary between 3% and 6%. In the ESMeD collaborative study of six Western European countries (Alonso et al., 2004) the one year prevalence was 3.9%. In the International Consortium of Psychiatric Epidemiology surveys, using the CIDI (Andrade et al., 2003), covering a wider range of countries, one year prevalences ranged from 1.2% for Japan, to 5.9% for the Netherlands. Recent US figures from the National Comorbidity Survey Replication (Kessler et al, 2005) give a higher 12 month prevalence of major depression of 6.7%. There is consistent female predominance of 2:1 or more, higher rates with lower social class and deprivation, a trend to a curvilinear relationship with age with highest rates in middle age, and high comorbidity with anxiety disorders and physical disorders. While prevalence has been studied extensively, incidence of first episodes and annual episode rates are less clear. To establish reliable incidence over a period requires studies employing two or more waves, the first to detect pre-existing disorder, the second to determine the occurrence rate of further new cases. Particularly problematic are lifetime rates. Estimation from a single interview is somewhat risky, since recall is likely to be incomplete and selective (Paykel, 2000). The Swedish Lundby study, which interviewed subjects from the same population twice with a 15 year gap, obtained lifetime estimates of approximately 32% in women and 17% in men (Rorsman et al., 1990), and a British study using rather different methods obtained somewhat similar values (Bebbington et al, 1989). Differential drop off in recall with age probably explains inferences from single interview studies that rates of depression are increasing Epidemiologia e Psichiatria Sociale, 15, 1, 2006