Cited by 2,168Schizophrenia research and treatmentMental Health Treatment and AccessMental Health and Psychiatry

The DOI matches its Crossref record; 223 of the 240 references it cites were found in a registry or an index, and 16 are not checked yet; none of the 40 sources its claims cite is checked for support yet.

A Systematic Review of the Prevalence of Schizophrenia

Open access

Saha, Sukanta, Chant, David, Welham, Joy, McGrath, John·2005·PLoS Medicine

DOI 10.1371/journal.pmed.0020141PMC PMC1140952

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Abstract

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.

Checked 2026-10-06 · 16 references not checked yet

AI snapshot

Written from the paper’s full text.

TL;DR

This systematic review collated 1,721 prevalence estimates from 188 studies across 46 countries to describe the distribution of schizophrenia prevalence and examine selected moderators. Median prevalence per 1,000 persons was 4.6 for point, 3.3 for period, 4.0 for lifetime, and 7.2 for lifetime morbid risk, with higher estimates in migrants and higher-quality studies and lower estimates in least developed countries.

Key findings

The review identified 1,721 prevalence estimates from 188 studies drawn from 46 countries, based on an estimated 154,140 potentially overlapping prevalent cases; there were 132 core studies, 15 migrant studies, and 41 studies of other special groups.
Median prevalence per 1,000 persons was 4.6 for point prevalence (10%–90% quantiles 1.9–10.0), 3.3 for period prevalence (1.3–8.2), 4.0 for lifetime prevalence (1.8–11.6 in the results text), and 7.2 for lifetime morbid risk (3.1–27.1).
There was no significant difference between males and females (F 1,72 = 0.68, p = 0.41; male:female median ratio 1.11, 10%–90% quantiles 0.50–1.70) or between urban, rural, and mixed sites (F 2,235 = 1.63, p = 0.20).
Migrant status was associated with higher prevalence: median migrant:native-born ratio 1.84 (10%–90% quantiles 0.86–6.41; F 1,2 = 5.57, p = 0.04). Prevalence was significantly lower in “least developed” countries than in “emerging” and “developed” sites (p = 0.04), and higher-quality studies had significantly higher estimates (highest versus lowest quality scores, p = 0.02).

Methods

Systematic review following MOOSE guidelines; studies with original prevalence data published January 1965–December 2002 were identified by searching MEDLINE, PsychINFO, EMBASE, and LILACS, checking references, and contacting authors; prison/forensic and genetic family studies were excluded.
Estimates were sorted with sequential filters into core, migrant, and other special groups, and into point, period, lifetime, lifetime morbid risk, not otherwise specified, and inpatient-census-derived types; a “most informative” rule selected discrete estimates from overlapping studies.
Analyses used cumulative plots and quantiles, with SAS proc univariate and proc mixed to control for within-study variation; combined prevalence estimates were used for planned sensitivity analyses, with Bonferroni correction for post hoc comparisons.

Limitations

The authors state that they may have missed studies or made data entry errors; filtering and extraction rules were necessarily ad hoc; combined prevalence estimates were not based on discrete data (8 of 94 studies contributed more than one prevalence type); standard errors could be imputed for only 26% of estimates; and the mixed urban/rural category was likely heterogeneous.
The authors also caution against excessive data analyses and note that contributing studies were not designed to test many hypotheses examined in the review.
Evident from the text: no formal pooled meta-analysis was performed because of heterogeneity and limited confidence limits, and the migrant analysis was restricted to five papers and 22 prevalence ratios after exclusions.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1371/journal.pmed.0020141

Cites

223 of 239 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 40 cited sources checked · 0 supported · 0 flagged

In the paper
“One study, which was allocated to “other special groups,” did provide confidence limits [29].”
§ A Systematic Review of the Prevalence of Schizophrenia > Methods > Presentation and Analyses of the Data
What the sources say
- Not checked yetcites [29] Nimgaonkar, 2000, Am J Psychiatry source
Strength:plain· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passes
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“These estimates were drawn from 46 countries, and were based on an estimated 154,140 potentially overlapping prevalent cases.”
- Also stated in: § The “Epidemiology” of Prevalence Estimates · plain
  “These studies provided 1,721 estimates and were drawn from 46 countries.”
§ A Systematic Review of the Prevalence of Schizophrenia > Abstract > Methods and Findings
Strength:plain· not yet calibratedn = 154,140
Tests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passes
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“A total of 1,721 prevalence estimates from 188 studies were identified.”
- Also stated in: § The “Epidemiology” of Prevalence Estimates · plain
  “The systematic review identified 188 studies that provided prevalence estimates [18,29,36–223].”
§ A Systematic Review of the Prevalence of Schizophrenia > Abstract > Methods and Findings
Load-bearingStrength:plain· not yet calibratedn = 154,140
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“A total of 1,721 prevalence estimates from 188 studies were identified.”
- Also stated in: § The “Epidemiology” of Prevalence Estimates · plain
  “These studies provided 1,721 estimates and were drawn from 46 countries.”
§ A Systematic Review of the Prevalence of Schizophrenia > Abstract > Methods and Findings
Load-bearingStrength:plain· not yet calibratedn = 154,140
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes
None of the sources cited for this claim have been checked yet.
In the paper
“Conversely, some religious groups had very low prevalence estimates—0.36 per 1,000 persons for Amish individuals [80] and 1.29 per 1,000 persons for Hutterite individuals [29].”
§ A Systematic Review of the Prevalence of Schizophrenia > Results > Other Special Group Studies
What the sources say
- Not checked yetcites [80] Egeland, 1983, Am J Psychiatry source
- Not checked yetcites [29] Nimgaonkar, 2000, Am J Psychiatry source
Strength:plain· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passes
None of the sources cited for this claim have been checked yet.
In the paper
“The World Health Organization ten-country study commented that the prognosis of schizophrenia [18] was better in developing than in developed nations, a finding that has been “clear and consistent” in general [22].”
- Also stated in: § Hypotheses · boosted
  “there is solid evidence showing that people with schizophrenia from developing countries tend to have better outcomes than individuals in developed nations [18,22].”
§ A Systematic Review of the Prevalence of Schizophrenia > Introduction > Key Research Questions about the Prevalence of Schizophrenia
What the sources say
- Not checked yetcites [18] Jablensky, 1992, Psychol Med Monogr Suppl source
- Not checked yetcites [22] Bresnahan, 2003, The epidemiology of schizophrenia
Load-bearingStrength:boosted· not yet calibratedCausal:correlational· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes
In the paper
“Given that the course of schizophrenia extends over months to decades, estimates of point prevalence based on 1 d are comparable to those based on 1 mo [5].”
§ A Systematic Review of the Prevalence of Schizophrenia > Introduction > Ways to Measure the Prevalence of Schizophrenia
What the sources say
- Not checked yetcites [5] Eaton, 1985, Epidemiol Rev source
Load-bearingStrength:plain· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes
None of the sources cited for this claim have been checked yet.
In the paper
“(a) males were more likely to develop schizophrenia than females (median male:female risk ratio = 1.4);”
- Also stated in: § Hypotheses · boosted
  “There is now strong evidence that males have an increased risk of developing schizophrenia [1,23].”
§ A Systematic Review of the Prevalence of Schizophrenia > Introduction
What the sources say
- Not checked yetcites [1] McGrath, 2004, BMC Med source
- Not checked yetcites [23] Aleman, 2003, Arch Gen Psychiatry source
Load-bearingStrength:boosted· not yet calibratedCausal:correlational· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Thus, forcing individual prevalence estimates into one pooled estimate loses important information.”
§ A Systematic Review of the Prevalence of Schizophrenia > Methods > Presentation and Analyses of the Data
Load-bearingStrength:plain· not yet calibratedCausal:direct· not yet calibrated
Tests✓ Asserted: passes? Checkable: unclear✓ Load-bearing: passes✓ Based: passes
- Rests on an assumption: Prevalence estimates for a disease are not static across time or place.
None of the sources cited for this claim have been checked yet.
In the paper
“(b) migrants were more likely to develop schizophrenia than native-born individuals (median risk ratio = 4.6);”
- Also stated in: § Hypotheses · plain
  “Migrants have a significantly increased risk of developing schizophrenia [1,33].”
§ A Systematic Review of the Prevalence of Schizophrenia > Introduction
What the sources say
- Not checked yetcites [1] McGrath, 2004, BMC Med source
- Not checked yetcites [33] Cantor-Graae, 2005, Am J Psychiatry source
Load-bearingStrength:plain· not yet calibratedCausal:correlational· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes
In the paper
“In the previous systematic review of the incidence of schizophrenia, we found that urban sites had significantly higher incidence rates of schizophrenia than mixed urban/rural sites (there were too few pure rural sites to make the direct urban versus rural comparison) [1].”
§ A Systematic Review of the Prevalence of Schizophrenia > Discussion > Urbanicity and the Prevalence of Schizophrenia
What the sources say
- Not checked yetcites [1] McGrath, 2004, BMC Med source
Strength:plain· not yet calibratedCausal:correlational· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passes
In the paper
“If we improve efficiencies within the current services, we can do somewhat better (22%).”
§ A Systematic Review of the Prevalence of Schizophrenia > Discussion > Conclusions
What the sources say
- Not checked yetcites [240] Andrews, 2004, Br J Psychiatry source
Strength:plain· not yet calibratedCausal:direct· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passes
In the paper
“In a utopian world, even if unlimited funding were available, three-quarters of the burden of schizophrenia would remain unavoidable [240].”
§ A Systematic Review of the Prevalence of Schizophrenia > Discussion > Conclusions
What the sources say
- Not checked yetcites [240] Andrews, 2004, Br J Psychiatry source
Load-bearingStrength:hedged· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes
None of the sources cited for this claim have been checked yet.
In the paper
“The median LMR estimate was 7.2 per 1,000, which is consistent with two other narrative reviews. Fremming [232], who reviewed 18 studies conducted in central Europe between 1926 and 1938, reported a mean LMR of 7.4 per 1,000, while Gottesman and Shields [233] reported a mean LMR of 8.0 per 1,000 in their classic review.”
§ A Systematic Review of the Prevalence of Schizophrenia > Discussion
What the sources say
- Not checked yetcites [232]
- Not checked yetcites [233]
Strength:plain· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passes
In the paper
“Many people with schizophrenia have persisting symptoms, despite the best mix of interventions we can offer.”
§ A Systematic Review of the Prevalence of Schizophrenia > Discussion > Conclusions
What the sources say
- Not checked yetcites [239] Andrews, 2003, Br J Psychiatry source
Strength:plain· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passes
In the paper
“These estimates are congruent with an earlier narrative review of 70 studies by Torrey [8], who reported an overall prevalence estimate of 4.6 per 1,000.”
§ A Systematic Review of the Prevalence of Schizophrenia > Discussion
What the sources say
- Not checked yetcites [8] Torrey, 1987, Br J Psychiatry source
Strength:plain· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passes
In the paper
“In our previous study of incidence of schizophrenia we found a male:female risk ratio of 1.40 [1].”
§ A Systematic Review of the Prevalence of Schizophrenia > Discussion > Sex and Schizophrenia
What the sources say
- Not checked yetcites [1] McGrath, 2004, BMC Med source
Load-bearingStrength:plain· not yet calibratedCausal:correlational· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes
In the paper
“For schizophrenia, with the current mix of interventions we can only reduce 13% of the burden.”
§ A Systematic Review of the Prevalence of Schizophrenia > Discussion > Conclusions
What the sources say
- Not checked yetcites [240] Andrews, 2004, Br J Psychiatry source
Strength:plain· not yet calibratedCausal:direct· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passes
None of the sources cited for this claim have been checked yet.
In the paper
“Recovery from schizophrenia clearly occurs [229–231], but it is unclear whether those who are free of positive symptoms but who have mild residual disability should be counted as “active” cases or not.”
§ A Systematic Review of the Prevalence of Schizophrenia > Discussion
What the sources say
- Not checked yetcites [229] Sartorius, 1986, Psychol Med source
- Not checked yetcites [230] Harding, 1987, Hosp Community Psychiatry
- Not checked yetcites [231] Harding, 1988, Schizophr Bull source
Load-bearingStrength:boosted· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes

Probably not a substantial claim. 29
It may state two separate claims as one. 21
The quote only partly states this claim. 1

A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“We identified 132 core studies, 15 migrant studies, and 41 studies based on other special groups.”
- Also stated in: § The “Epidemiology” of Prevalence Estimates · plain
  “There were 132 core studies, 15 migrant studies (of which three overlap with discrete core), and 41 studies that reported the prevalence of schizophrenia in other special groups.”
§ A Systematic Review of the Prevalence of Schizophrenia > Abstract > Methods and Findings
Strength:plain· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passes
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“These estimates were drawn from 46 countries, and were based on an estimated 154,140 potentially overlapping prevalent cases.”
- Also stated in: § The “Epidemiology” of Prevalence Estimates · hedged
  “The prevalence estimates were based on an estimated total of 154,140 potentially overlapping cases.”
§ A Systematic Review of the Prevalence of Schizophrenia > Abstract > Methods and Findings
Strength:hedged· not yet calibratedn = 154,140
Tests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passes
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“We identified 132 core studies, 15 migrant studies, and 41 studies based on other special groups.”
- Also stated in: § The “Epidemiology” of Prevalence Estimates · plain
  “There were 132 core studies, 15 migrant studies (of which three overlap with discrete core), and 41 studies that reported the prevalence of schizophrenia in other special groups.”
§ A Systematic Review of the Prevalence of Schizophrenia > Abstract > Methods and Findings
Strength:plain· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passes
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“We identified 132 core studies, 15 migrant studies, and 41 studies based on other special groups.”
- Also stated in: § The “Epidemiology” of Prevalence Estimates · plain
  “There were 132 core studies, 15 migrant studies (of which three overlap with discrete core), and 41 studies that reported the prevalence of schizophrenia in other special groups.”
§ A Systematic Review of the Prevalence of Schizophrenia > Abstract > Methods and Findings
Strength:plain· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passes
Probably not a substantial claim. The paper’s conclusions may not depend on it.
None of the sources cited for this claim have been checked yet.
In the paper
“However, we note that prevalence estimates in some homeless populations were very high—300 per 1,000 persons for Sydney homeless individuals [194] and 131 per 1,000 persons for Los Angeles homeless individuals [118].”
§ A Systematic Review of the Prevalence of Schizophrenia > Results > Other Special Group Studies
What the sources say
- Not checked yetcites [194] Virgona, 1993, Aust N Z J Psychiatry source
- Not checked yetcites [118] Koegel, 1988, Arch Gen Psychiatry source
Strength:plain· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passes
It may state two separate claims as one.
In the paper
“While the incidence of the disorder is relatively low (median value 15.2 per 100,000 persons per year) [1], the condition is one of the major contributors to the global burden of disease [2].”
§ A Systematic Review of the Prevalence of Schizophrenia > Introduction
What the sources say
- Not checked yetcites [1] McGrath, 2004, BMC Med source
Strength:plain· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passes
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“(c) individuals in urban sites had a higher risk of developing schizophrenia than those in mixed urban/rural sites.”
§ A Systematic Review of the Prevalence of Schizophrenia > Introduction
What the sources say
- Not checked yetcites [1] McGrath, 2004, BMC Med source
Load-bearingStrength:plain· not yet calibratedCausal:correlational· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes
Probably not a substantial claim.
In the paper
“This systematic review conforms to the guidelines outlined by the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) recommendations [26].”
§ A Systematic Review of the Prevalence of Schizophrenia > Methods > Identification of Studies
What the sources say
- Not checked yetcites [26] Stroup, 2000, JAMA source
Strength:plain· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passes
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“In brief, we found that the incidence of schizophrenia varied widely between sites (persons, median = 15.2 per 100,000; 10%–90% quantiles = 7.7–43.0).”
§ A Systematic Review of the Prevalence of Schizophrenia > Introduction
What the sources say
- Not checked yetcites [1] McGrath, 2004, BMC Med source
Load-bearingStrength:plain· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes
Probably not a substantial claim.
None of the sources cited for this claim have been checked yet.
In the paper
“The reviews of Odegaard [15], and Larsson and Sjogren [16] noted that, for low-incidence disorders such as schizophrenia, summation of age-specific incidence rates gives almost the same result as other more complicated methods of calculation [17].”
§ A Systematic Review of the Prevalence of Schizophrenia > Introduction > Ways to Measure the Prevalence of Schizophrenia
What the sources say
- Not checked yetcites [15] Odegaard, 1946, Psychiatr Q source
- Not checked yetcites [16] Larsson, 1954, Acta Psychiatr Neurol Scand
- Not checked yetcites [17] Alda, 1989, Schizophr Res source
Strength:plain· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passes
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“The search methodology for this review was identical to that of our previous review paper on incidence of schizophrenia [1].”
§ A Systematic Review of the Prevalence of Schizophrenia > Methods > Identification of Studies
What the sources say
- Not checked yetcites [1] McGrath, 2004, BMC Med source
Strength:plain· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passes
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“Our findings lend weight to the commentary by Ran and Yu-Hai Chen [25], drawing attention to the different features of schizophrenia in the developing world.”
§ A Systematic Review of the Prevalence of Schizophrenia > Discussion > Economic Status and Schizophrenia
What the sources say
- Not checked yetcites [25] Ran, 2004, Lancet source
Strength:hedged· not yet calibratedCausal:correlational· not yet calibrated
Tests✓ Asserted: passes✗ Checkable: fails✗ Load-bearing: fails✓ Based: passes
Probably not a substantial claim. It may be too vague to check against evidence. The paper’s conclusions may not depend on it.
In the paper
“however, the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) [3], reported that the lifetime prevalence of schizophrenia is “usually estimated to be between 0.5% and 1%.””
§ A Systematic Review of the Prevalence of Schizophrenia > Discussion
What the sources say
- Not checked yetcites [3]
Strength:hedged· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passes
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“Recently, a study from China examined whether this unexpected sex ratio was due to differential suicide rates in males with schizophrenia [24]; however, this did not seem to explain the female excess.”
§ A Systematic Review of the Prevalence of Schizophrenia > Discussion > Economic Status and Schizophrenia
What the sources say
- Not checked yetcites [24] Phillips, 2004, Lancet source
Strength:hedged· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passes
It may state two separate claims as one.
In the paper
“Because narrative reviews conclude that the course of the illness tends to be more severe in men than in women [235], we assumed that this would be reflected in a higher prevalence in males than females.”
§ A Systematic Review of the Prevalence of Schizophrenia > Discussion > Sex and Schizophrenia
What the sources say
- Not checked yetcites [235] Leung, 2000, Acta Psychiatr Scand Suppl source
Load-bearingStrength:hedged· not yet calibratedCausal:correlational· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes
Probably not a substantial claim.
None of the sources cited for this claim have been checked yet.
In the paper
“However, one in a hundred is an overestimate—our systematic review agrees with two previous reviews showing that the LMR for schizophrenia is between seven and eight per 1,000.”
§ A Systematic Review of the Prevalence of Schizophrenia > Discussion
What the sources say
- Not checked yetcites [232]
- Not checked yetcites [233]
Load-bearingStrength:plain· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes
It may state two separate claims as one.
- The authors state this as an assumption: The oft-quoted statistic that schizophrenia affects about one in a hundred derives from LMR data.
None of the sources cited for this claim have been checked yet.
In the paper
“Furthermore, in the absence of clear guidelines on how to synthesize descriptive studies [26,237], many of the rules we used to filter studies and extract data were necessarily ad hoc.”
§ A Systematic Review of the Prevalence of Schizophrenia > Discussion > Caveats
What the sources say
- Not checked yetcites [26] Stroup, 2000, JAMA source
- Not checked yetcites [237] von Elm, 2004, BMJ source
Strength:plain· not yet calibratedCausal:direct· not yet calibrated
Tests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passes
Probably not a substantial claim. The paper’s conclusions may not depend on it.

49 of 49

The authors state this as an assumption.
The course of schizophrenia does not vary according to migrant status.
“Assuming that the course of the illness does not vary according to migrant status, based on combined prevalence estimates for persons, we predicted that the prevalence of schizophrenia would be higher in migrants than in native-born individuals.”
The paper relies on this without support.
Studies that use comprehensive case ascertainment methods identify more cases than those that rely on fewer recruitment sources.
“For example, studies that use comprehensive case ascertainment methods (e.g., “door-knock” surveys, inpatient and outpatient records, general practitioner surveys, and/or surveys based on other community sources), should identify more cases than those that rely on fewer recruitment sources.”
The paper relies on this without support.
Prevalence estimates for a disease are not static across time or place.
“Based on first principles, there is no reason to assume that prevalence estimates for a disease remain static across time or place.”
The authors state this as an assumption.
The oft-quoted statistic that schizophrenia affects about one in a hundred derives from LMR data.
“It is reasonable to assume that the oft-quoted statistic that “schizophrenia affects about one in a hundred” derives from LMR data (see [234]).”

4 of 4

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

Abstract and results give different lifetime-prevalence quantiles
Minor
The abstract gives lifetime-prevalence 10%-90% quantiles of 1.6-12.1 per 1,000, whereas the results give 1.8-11.6 per 1,000.
Discussion understates the reported spread of prevalence estimates
Minor
The discussion describes 3.4-fold variation for point prevalence and 4.6-fold for period prevalence. The results instead report approximately 5-fold and 6.5-fold variation for those types, respectively.
Study-category totals do not account for overlapping studies
Minor
The three category counts add to 188, the reported total number of studies. But the paper says 11 studies appear in two categories, so the counts cannot represent 188 distinct studies.
Country counts account for only 33 special-group studies
Minor
The counts listed for the 14 countries sum to 33, not the stated 41 special-group studies.
Reported 41 · recomputed 33

4 of 4

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Authors: Saha, S., Chant, D., Welham, J., & McGrath, J.
Affiliations: Park Centre for Mental Health (AU)
The University of Queensland (AU)
Corresponding author: McGrath, John
ORCID: Saha, Sukanta
McGrath, John
Venue: PLoS Medicine
Publisher: Public Library of Science (PLoS)
Published: 2005-05-31
Volume: 2
Issue: 5
Pages: e141
ISSN: 1549-1277 (ISSN-L)
1549-1676
DOI: 10.1371/journal.pmed.0020141
PMC: PMC1140952
OpenAlex: W2113758182
Semantic Scholar: b75013fbff8cc614ea7c3e41ec1aac57ad4efc20
Cited by: 2,168
References: 240
Citations by year: 2026: 82 · 2025: 94 · 2024: 120 · 2023: 139 · 2022: 134 · 2021: 132 · 2020: 137 · 2019: 128 · 2018: 108 · 2017: 114 · 2016: 126 · 2015: 128 · 2014: 122 · 2013: 117 · 2012: 111
FWCI: 6.37
Type: journal article
Language: en
Open access: gold
doi.org
Licence: cc-by
creativecommons.org/licenses/by/4.0/ (unspecified)
Locations: PLoS Medicine (publishedVersion, cc-by)
Europe PMC (PubMed Central) (publishedVersion, cc-by)
PubMed Central (publishedVersion, cc-by)
PubMed (publishedVersion)
RePEc: Research Papers in Economics (submittedVersion)
DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Figshare (submittedVersion, cc-by)
Griffith Research Online (submittedVersion, cc-by)
Funders: Stanley Medical Research Institute
Topics: Health Sciences › Medicine › Psychiatry and Mental health › Schizophrenia research and treatment
Health Sciences › Medicine › Psychiatry and Mental health › Mental Health Treatment and Access
Social Sciences › Arts and Humanities › Philosophy › Mental Health and Psychiatry
Keywords: schizophrenia, prevalence, lifetime prevalence, point prevalence, period prevalence, migrants, urban-rural differences, sex differences, study quality, risk factors, health planning, risk factor epidemiology
MeSH terms: Female, Humans, Male, Rural Population, Schizophrenia, Sex Factors, Social Class, Urban Population, Prevalence, Epidemiologic Studies, Needs Assessment

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A Systematic Review of the Prevalence of Schizophrenia

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