Schizophrenia: A Concise Overview of Incidence, Prevalence, and Mortality

Recent systematic reviews have encouraged the psychiatric researchcommunity to reevaluate the contours of schizophrenia epidemiology.This paper provides a concise overview of three related systematicreviews on the incidence, prevalence, and mortality associatedwith schizophrenia. The reviews shared key methodological featuresregarding search strategies, analysis of the distribution ofthe frequency estimates, and exploration of the influence ofkey variables (sex, migrant status, urbanicity, secular trend,economic status, and latitude). Contrary to previous interpretations,the incidence of schizophrenia shows prominent variation betweensites. The median incidence of schizophrenia was 15.2/100,000persons, and the central 80% of estimates varied over a fivefoldrange (7.7–43.0/100,000). The rate ratio for males:femaleswas 1.4:1. Prevalence estimates also show prominent variation.The median lifetime morbid risk for schizophrenia was 7.2/1,000persons. On the basis of the standardized mortality ratio, peoplewith schizophrenia have a two- to threefold increased risk ofdying (median standardized mortality ratio = 2.6 for all-causemortality), and this differential gap in mortality has increasedover recent decades. Compared with native-born individuals,migrants have an increased incidence and prevalence of schizophrenia.Exposures related to urbanicity, economic status, and latitudeare also associated with various frequency measures. In conclusion,the epidemiology of schizophrenia is characterized by prominentvariability and gradients that can help guide future research. incidence • mortality • prevalence • review • schizophrenia