Epidemiology of bipolar disorders

Abstract

Information about the epidemiology of bipolar disorders is essential for providing a framework for the formulation of effective mental health policy. In the last two decades, population surveys of psychiatric morbidity in adults have been conducted and as a result details on the frequency, risk factor, social disabilities, and service use rates of mental disorders are now available. Epidemiological findings on bipolar disorders are discussed on the light of results from recent large population-based surveys namely the Epidemiological Catchment Area Study (ECA), the National Comorbidity Survey (NCS), the OPCS Survey of Psychiatric Morbidity in Great Britain, the Brazilian Multicentric Study of Psychiatric Morbidity, and the longitudinal studies conducted in Zurich by Angst. Prevalence rates for bipolar disorder were generally low, regardless setting, the type of instrument used for generating psychiatric diagnosis, and the time periods by which prevalence is defined. Since the introduction of the concept of bipolar spectrum, broadening the boundaries of the disease, the estimate rates have been found to be substantially higher. Such rates still need to be validated by populational-based studies. Bipolar disorder is as prevalent in women as in men, more common among singles and separated or divorced people. Those affected by the disease are more likely to use medical services and to be hospitalized. The cost-effectiveness of treatments must be balanced with the high individual and social impact associated to the bipolar illness.