A systematic review of the prevalence of schizophrenia

Saha, Sukanta, Chant, David, Welham, Joy and McGrath, John (2005) A systematic review of the prevalence of schizophrenia. Plos Medicine, 2 5: 0413-0433. doi:10.1371/journal.pmed.0020141

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Author Saha, Sukanta
Chant, David
Welham, Joy
McGrath, John
Title A systematic review of the prevalence of schizophrenia
Journal name Plos Medicine   Check publisher's open access policy
ISSN 1549-1277
Publication date 2005-01-01
Sub-type Critical review of research, literature review, critical commentary
DOI 10.1371/journal.pmed.0020141
Open Access Status DOI
Volume 2
Issue 5
Start page 0413
End page 0433
Total pages 21
Editor V. Barbour
B. Cohen
G. Yamey
S. E. Hyman
Place of publication San Francisco, U.S.A.
Publisher Public Library of Science
Language eng
Subject C1
321021 Psychiatry
730211 Mental health
111714 Mental Health
110319 Psychiatry (incl. Psychotherapy)
Formatted abstract
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).

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.
Keyword Medicine, general & internal
Australian Western Desert
Christchurch psychiatric epidemiology
Term functional-psychosis
Major mental-disorders
Non-hispanic Whites
3 different areas
Lifetime prevalence
Community sample
Rural Ireland
Q-Index Code C1
Additional Notes Copyright: © 2005 Saha et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Article number: e141

Document type: Journal Article
Sub-type: Critical review of research, literature review, critical commentary
Collections: Excellence in Research Australia (ERA) - Collection
2006 Higher Education Research Data Collection
School of Medicine Publications
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Citation counts: TR Web of Science Citation Count  Cited 673 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 751 times in Scopus Article | Citations
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Created: Wed, 15 Aug 2007, 16:06:34 EST