A Systematic Review of the Prevalence of Schizophrenia

By S. Saha, D. Chant, J. Welham, John J. McGrath. PLoS Medicine, 2005

2,117 citations recorded by the source corpus.

Background Understanding the prevalence of schizophrenia has important implications for both health service planning and risk factor epidemiology. The aims of this review are to systematically identify and collate studies describing the prevalence of schizophrenia, to summarize the findings of these studies, and to explore selected factors that may influence prevalence estimates. Methods and Findings Studies with original data related to the prevalence of schizophrenia (published 1965–2002) were identified via searching electronic databases, reviewing citations, and writing to authors. These studies were divided into “core” studies, “migrant” studies, and studies based on “other special groups.” Between- and within-study filters were applied in order to identify discrete prevalence estimates. Cumulative plots of prevalence estimates were made and the distributions described when the underlying estimates were sorted according to prevalence type (point, period, lifetime, and lifetime morbid risk). Based on combined prevalence estimates, the influence of selected key variables was examined (sex, urbanicity, migrant status, country economic index, and study quality). A total of 1,721 prevalence estimates from 188 studies were identified. These estimates were drawn from 46 countries, and were based on an estimated 154,140 potentially overlapping prevalent cases. We identified 132 core studies, 15 migrant studies, and 41 studies based on other special groups. The median values per 1,000 persons (10%–90% quantiles) for the distributions for point, period, lifetime, and lifetime morbid risk were 4.6 (1.9–10.0), 3.3 (1.3–8.2), 4.0 (1.6–12.1), and 7.2 (3.1–27.1), respectively. Based on combined prevalence estimates, we found no significant difference (a) between males and females, or (b) between urban, rural, and mixed sites. The prevalence of schizophrenia in migrants was higher compared to native-born individuals: the migrant-to-native-born ratio median (10%–90% quantile) was 1.8 (0.9–6.4). When sites were grouped by economic status, prevalence estimates from “least developed” countries were significantly lower than those from both “emerging” and “developed” sites (p = 0.04). Studies that scored higher on a quality score had significantly higher prevalence estimates (p = 0.02). Conclusions There is a wealth of data about the prevalence of schizophrenia. These gradients, and the variability found in prevalence estimate distributions, can provide direction for future hypothesis-driven research.

Subfields: Clinical Psychology, Psychiatry and Mental health, Social Psychology

View Paper: https://www.semanticscholar.org/paper/b75013fbff8cc614ea7c3e41ec1aac57ad4efc20

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Citations in the corpus

A systematic review of mortality in schizophrenia: is the differential mortality gap worsening over time? (2007, methodology): “We applied a similar sorting algorithm to that used in our previous reviews of schizophrenia.(19,20) Briefly, the mortality estimates were sorted into different causes of death.”
ASD and schizophrenia show distinct developmental profiles in common genetic overlap with population-based social-communication difficulties (2017, neutral): “The disorder has a lifetime prevalence of ~1%9 and is characterised by hallucinations, delusions, disorganized speech or behaviour, apathy and lack of emotional reactivity2.”
The Global Burden of Mental, Neurological and Substance Use Disorders: An Analysis from the Global Burden of Disease Study 2010 (2015, methodology): “For each disorder, prevalence data were assembled by conducting systematic reviews of the published and gray literature to capture data on prevalence, incidence, remission, duration, and excess mortality [16,18,20,21,27–29].”
Schizophrenia: a concise overview of incidence, prevalence, and mortality. (2008, background): “Do we have sufficient data to build integrated and cohesive models of the epidemiology of schizophrenia in populations? Certainly, with respect to the stock and inflow variables, there is a wealth of data on the incidence and prevalence of schizophrenia (4, 19).”
Global variation in the prevalence and incidence of major depressive disorder: a systematic review of the epidemiological literature (2012, result): “Pursuing the reason for this finding was outside the scope of this study; however, similar unanticipated results have been reported in the literature pertaining to the prevalence of schizophrenia (Saha et al. 2005).”
The Prevalence of Mental Disorders among the Homeless in Western Countries: Systematic Review and Meta-Regression Analysis (2008, neutral): “8% when only schizophrenia is reported [70].”
Royal Australian and New Zealand College of Psychiatrists clinical practice guidelines for the management of schizophrenia and related disorders (2016, background): “As one would expect for a heterogeneous group of disorders, frequency estimates related to the incidence and prevalence of schizophrenia vary (McGrath et al., 2004; Saha et al., 2005).”
Experiences of Domestic Violence and Mental Disorders: A Systematic Review and Meta-Analysis (2012, methodology): “The quality of included studies was independently appraised by two reviewers (KT and SO) using criteria adapted from validated tools [22,23,24,25].”
Glutamate and dopamine in schizophrenia: an update for the 21st century (2015, background): “It has a lifetime prevalence of about 0.7%, with a peak age of onset in the early twenties in men, and three or four years later in women (Saha et al., 2005).”
Rare and Common Variants: Twenty arguments (2011, background): “Schizophrenia, a disease with a very high heritability (as inferred from twin studies) and for which very few replicated hits have been identified by GWASs, despite extensive scans, nevertheless shows such demographic influences as whether the parents live in rural or urban areas (disease rates are ”