Psychiatric epidemiology†

Neuropsychiatric disorders represent a significant cause of morbidity, accounting for over 10% of disability worldwide, more than is attributable to cardiovascular disease or cancer. In developed-market economies, this figure rises to one-fourth of all disability. Besides their direct effects on morbidity, mental disorders are also independently associated with elevations in all-cause mortality and are negative predictors of recovery when associated with medical illnesses like cardiovascular disease and diabetes mellitus. Several large-based epidemiological studies conducted over the last few decades have described the incidence and prevalence of major psychiatric conditions. These include the Epidemiologic Catchment Area study, the National Comorbidity Survey, National Comorbidity Survey Replication, and the World Mental Health Survey. Overall, these studies found lifetime prevalences of mental disorders ranging from one-quarter to nearly one-half of the population studied. US-based surveys report 1-year prevalence rates of nearly 30%. Anxiety disorders are the most common type of psychiatric illness diagnosed, followed by mood disorders. While the majority of psychiatric disorders are mild or moderate, there is evidence that, when untreated, these conditions can develop into more serious illness, arguing the importance of early detection. Despite the high burden of psychiatric illness, most patients with a mental illness do not receive treatment. This article provides an overview of the incidence and prevalence of common psychiatric disorders and characteristics of the manifestation of these disorders within a population.