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Epidemiology of schizophrenia and related disorders

Epidemiological approaches to understanding the frequency, distribution, and determinants of psychotic disorders, such as schizophrenia, have played a vital role in delineating the aetiology and course of these conditions for almost a century. Despite several milestones, reviewed in this chapter, many methodological and clinical aspects of these disorders continue to provide challenges to studying the epidemiology of psychotic disorders, including issues of case definition, case ascertainment, and study design. After summarizing these challenges, we review the current neuropsychiatric epidemiologic knowledge of the incidence, prevalence, and aetiology of psychotic disorders. Here, we also provide a contemporary overview of the role that genetic, neurodevelopmental, demographic and environmental risk factors, including inflammation, traumatic life events, substance abuse, urban living, and minority status have on risk, course, and outcome of psychotic disorder. We conclude with future directions required to elucidate the interplay of these factors in contributing to the global burden of psychotic disorders.