Epidemiology of psychiatric illness
The science of epidemiology has much to offer in assisting clinical investigators and practicing psychiatrists to place the work on inpatient units and outpatient clinics into context. Epidemiologists first emphasize the importance of case identification and finding (who is a case of, for example, major depression and who is not). Once a method of case identification is established, the frequency and distribution of cases in varying populations (such as the community or general medicine clinic) can be established. New cases can be enumerated from a population at risk over time (for example, estimating the one-year incidence of major depression in a community). Epidemiology has been most instrumental through informing our current nomenclature as to the nature and extent of psychiatric disorders which are comorbid. Mental health service use, especially in community-based populations, is another focus of psychiatric epidemiology. Finally, psychiatric epidemiology assists investigators and clinicians to identify risk factors for psychiatric disorders, ranging from demographic factors to biological risks. The preliminary explorations into risk provide the basis for more extensive studies of etiology.
