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

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.

Verified 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

  • Findingown data

    Of the 132 core studies, 24 were identified for lifetime prevalence.

    “Of the 132 core studies, we identified 21 studies for point prevalence, 34 studies for period prevalence, and 24 studies for lifetime prevalence.”
    Quote in the paperNot a substantial claim
  • Findingown data

    The median lifetime prevalence of schizophrenia for persons was 4.0 per 1,000, based on 29 estimates, with 10% and 90% quantiles from 1.8 to 11.6 per 1,000 (a 6.4-fold difference).

    “The median lifetime prevalence for persons (based on 29 estimates) was 4.0 per 1,000, and the 10% and 90% quantiles ranged from 1.8 to 11.6 per 1,000 (a 6.4-fold difference).”
    Quote in the paperSubstantial claim
  • Findingown data

    Four studies reported prevalence only within narrow age strata without providing an overall rate.

    “Four studies [59,120,169,224] reported prevalence only within narrow age strata without providing an overall rate.”
    Quote in the paperNot a substantial claim
  • Findingown data

    The median lifetime morbid risk per 1,000 persons was 7.2 (10%-90% quantiles 3.1-27.1).

    “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.”
    Quote in the paperSubstantial claim
  • Findingcitation

    One study allocated to "other special groups" did provide confidence limits.

    “One study, which was allocated to “other special groups,” did provide confidence limits [29].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [29] Nimgaonkar, 2000, Am J Psychiatry source

      Not checked in the free run.

  • Classified as probably not a substantial claim. 29
  • May combine two claims. 21
  • The quote only partly states this claim. 1

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The review identified 132 core studies.

    “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.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    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).

    “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).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The electronic search identified 1,112 papers (85% of the total papers included in the study).

    “The electronic search identified 1,112 papers (85% of the total papers included in the study), while manual reference checking identified an additional 142 references (11%).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The prevalence estimates were based on an estimated 154,140 potentially overlapping prevalent cases.

    “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.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Standard errors could be imputed for only 26% of the prevalence estimates, drawn from less than half (45%) of the discrete core studies.

    “However, we were able to impute standard errors for only 26% of the prevalence estimates, which were drawn from less than half (45%) of the discrete core studies.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The review identified 41 studies based on other special groups.

    “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.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The 132 core studies provided from one to 13 prevalence estimates per study.

    “The 132 core studies provided from one to 13 prevalence estimates per study.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Nine core studies reported lifetime morbid risk.

    “There were nine studies that reported LMR.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    98 studies published in languages other than English were identified.

    “We identified 98 studies that were published in languages other than English.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Responses from 31 authors provided an additional 53 references (4%).

    “We received responses from 31 authors (see Acknowledgments for full list), who provided an additional 53 references (4%).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Manual reference checking identified an additional 142 references (11%).

    “The electronic search identified 1,112 papers (85% of the total papers included in the study), while manual reference checking identified an additional 142 references (11%).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    After translation, 17 of the non-English studies were included in this review.

    “After translation 17 of these studies were included in this review.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The median period prevalence of schizophrenia for persons was 3.3 per 1,000, based on 42 estimates, with 10% and 90% quantiles from 1.3 to 8.2 per 1,000 (a 6.5-fold difference).

    “The median period prevalence for persons (based on 42 estimates) was 3.3 per 1,000, and the 10% and 90% quantiles ranged from 1.3 to 8.2 per 1,000 (a 6.5-fold difference).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The review identified 15 migrant studies.

    “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.”
    Quote in the paperNot a substantial claim

  • The quote only partly states this claim.

    Findingown data

    Prevalence estimates for migrant groups tend to be higher than estimates for native-born populations.

    “As predicted, prevalence estimates for migrant groups tend to be higher than estimates for native-born populations.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The median prevalence estimates for emerging economies are numerically higher than those for the richest countries, but the difference is not statistically significant.

    “Furthermore, the median prevalence estimates for emerging economies are numerically higher than those for the richest countries. While not statistically significant, the results did identify many prevalence studies from the developing world where females outnumbered males.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    Two prevalence types (LMR and inpatient-census-derived data) had distributions for persons that were higher than distributions for both males and females separately.

    “Two of the prevalence types (LMR and inpatient-census-derived data) had distributions for persons that were higher than distributions for both males and females separately.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Combined prevalence estimate distributions for persons differed significantly by quality score tercile (F 2,105 = 4.79, p = 0.01), with the highest quality studies reporting significantly higher prevalence estimates than the other two terciles (highest versus lowest quality scores, p = 0.02).

    “When the combined prevalence estimates for persons were divided into quality score terciles, the prevalence estimate distributions were significantly different (F 2,105 = 4.79, p = 0.01), with the highest quality studies reporting significantly higher prevalence estimates than the other two terciles (highest versus lowest quality scores, p = 0.02) (Table 13; Figure 14).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The median migrant:native-born prevalence ratio was 1.84, based on 22 prevalence ratios, with 10% and 90% quantiles from 0.86 to 6.41 (approximately a 7.5-fold difference).

    “Based on 22 prevalence ratios, the median migrant:native-born prevalence ratio was 1.84 and the 10% and 90% quantiles were 0.86 to 6.41 (approximately a 7.5-fold difference) (see Table 10; Figure 11).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The median lifetime morbid risk (LMR) for schizophrenia for persons was 7.2 per 1,000, based on 27 estimates, with 10% and 90% quantiles from 3.1 to 27.1 per 1,000 (an 8.7-fold difference).

    “The median LMR for persons (based on 27 estimates) was 7.2 per 1,000, and the 10% and 90% quantiles ranged from 3.1 to 27.1 per 1,000 (a 8.7-fold difference) (see Table 6).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The median male:female prevalence estimate ratio was 1.11, based on 57 ratios, with 10% and 90% quantiles from 0.50 to 1.70 (approximately a 3.4-fold difference).

    “For the male:female estimate ratio (based on 57 ratios), the median value was 1.11, and the 10% and 90% quantiles were 0.50 to 1.70 (approximately a 3.4-fold difference) (see Figure 9).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Prevalence estimate distributions differed significantly by economic status of country (F 2,85 = 3.57, p = 0.03), with the difference attributed to lower prevalence estimates for less developed economies (developed versus least developed, F 1,74 = 6.55, p = 0.04).

    “When divided by this criterion, the prevalence estimate distributions were significantly different (F 2,85 = 3.57, p = 0.03), with the difference attributed to the lower prevalence estimate distribution for the less developed economies (developed versus least developed, F 1,74 = 6.55, p = 0.04).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The review identified 1,721 estimates from 188 studies, drawn from 46 countries, based on an estimated 154,140 potentially overlapping prevalent cases.

    “There is a wealth of data available on the prevalence of schizophrenia—a total of 1,721 estimates from 188 studies were identified in this systematic review. These estimates were drawn from 46 countries, and were based on an estimated 154,140 potentially overlapping prevalent cases.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Mixed urban/rural prevalence estimates were higher than urban and rural rates, but this difference was not statistically significant (F 2,235 = 1.63, p = 0.20).

    “While the mixed urban/rural estimates were higher than urban and rural rates, this difference was not statistically significant (F 2,235 = 1.63, p = 0.20), nor were urban estimates significantly different from rural estimates (F 1,120 = 0.95, p = 0.33).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The median NOS prevalence of schizophrenia for persons was 2.7 per 1,000, based on 32 estimates, with 10% and 90% quantiles from 1.4 to 4.8 per 1,000 (a 3.4-fold difference).

    “Based on the distribution of these prevalence estimates, the median prevalence was 2.7 per 1,000 for persons, and the 10% and 90% quantiles ranged from 1.4 to 4.8 per 1,000 (a 3.4-fold difference).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingcitation

    Prevalence estimates in some homeless populations were very high: 300 per 1,000 for Sydney homeless individuals and 131 per 1,000 for Los Angeles homeless individuals.

    “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].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [194] Virgona, 1993, Aust N Z J Psychiatry source

      Not checked in the free run.

    • cites [118] Koegel, 1988, Arch Gen Psychiatry source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The incidence of schizophrenia is relatively low (median value 15.2 per 100,000 persons per year).

    “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].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [1] McGrath, 2004, BMC Med source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Individuals in urban sites had a higher risk of developing schizophrenia than those in mixed urban/rural sites.

    “(c) individuals in urban sites had a higher risk of developing schizophrenia than those in mixed urban/rural sites.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [1] McGrath, 2004, BMC Med source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    This systematic review conforms to the guidelines outlined by the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) recommendations.

    “This systematic review conforms to the guidelines outlined by the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) recommendations [26].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [26] Stroup, 2000, JAMA source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    The incidence of schizophrenia varies widely between sites (median = 15.2 per 100,000; 10%-90% quantiles = 7.7-43.0).

    “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).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [1] McGrath, 2004, BMC Med source

      Not checked in the free run.

  • May combine two claims.

    Study design and conductreasoning

    Sequential filters were applied to identify discrete prevalence estimates and avoid double counting.

    “Thus, a key feature of this study is the application of sequential filters in order to identify discrete prevalence estimates.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Disagreements in data checking were resolved by consensus.

    “When disagreements arose, these were resolved by consensus.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    For low-incidence disorders such as schizophrenia, summation of age-specific incidence rates gives almost the same result as other more complicated methods of calculating lifetime morbid risk.

    “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].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [15] Odegaard, 1946, Psychiatr Q source

      Not checked in the free run.

    • cites [16] Larsson, 1954, Acta Psychiatr Neurol Scand

      Not checked in the free run.

    • cites [17] Alda, 1989, Schizophr Res source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductreasoning

    The analyses were restricted to a limited set of planned sensitivity analyses, each with a priori directional hypotheses, and post hoc analyses applied Bonferroni correction.

    “we restricted the analyses to a limited set of planned sensitivity analyses, each with a priori directional hypotheses, and, for post hoc analyses, applied multiple comparison corrections to the nominal significance levels by a Bonferroni correction.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Two or more of the authors checked all data used in the analysis.

    “Two or more of the authors checked all data used in the analysis.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    Studies were given quality points based on operationalized features related to optimal research design and quality of reporting.

    “studies were given “quality points” based on operationalized features related to (a) optimal research design (e.g., higher scores for greater coverage, face-to-face interview versus chart diagnosis, and reliability of instruments), and (b) quality of reporting (e.g., provision of numerator and denominator, and description of diagnostic criteria).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    The search methodology for this review was identical to that of the previous review paper on incidence of schizophrenia.

    “The search methodology for this review was identical to that of our previous review paper on incidence of schizophrenia [1].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [1] McGrath, 2004, BMC Med source

      Not checked in the free run.

  • May combine two claims.

    Interpretationnone given

    While the incidence of schizophrenia is higher in urban than rural settings, this is not reflected in the overall prevalence data.

    “While the incidence of schizophrenia is higher in urban than rural settings, this is not reflected in the overall prevalence data.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    The estimates from other special groups are not readily comparable, but these studies reported a wide range of prevalence estimates.

    “With respect to the studies included in the category “other special groups,” the estimates are not readily comparable, but it is interesting to note that these studies reported a wide range of prevalence estimates (e.g., high in homeless populations and low in certain religious groups).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationown data

    The findings lend weight to the commentary by Ran and Yu-Hai Chen drawing attention to the different features of schizophrenia in the developing world.

    “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.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [25] Ran, 2004, Lancet source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    DSM-IV reported that the lifetime prevalence of schizophrenia is usually estimated to be between 0.5% and 1%.

    “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%.””
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [3]

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    A study from China examined whether the unexpected sex ratio was due to differential suicide rates in males with schizophrenia, but this did not seem to explain the female excess.

    “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.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [24] Phillips, 2004, Lancet source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Narrative reviews conclude that the course of schizophrenia tends to be more severe in men than in women.

    “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.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [235] Leung, 2000, Acta Psychiatr Scand Suppl source

      Not checked in the free run.

  • May combine two claims.

    Study design and conductreasoning

    The estimates from mixed urban/rural studies are likely to be very heterogeneous, and allocating studies to the mixed category if there was any possibility that rural sectors were included would have made any true difference between urban versus mixed urban/rural more difficult to detect.

    “Concerning the analyses for urbanicity, the estimates from mixed urban/rural studies are likely to be very heterogeneous. Indeed, we allocated studies to the mixed category if there was any possibility that rural sectors were included. This bias would have made any true difference between urban versus mixed urban/rural more difficult to detect.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    The lack of coherence between sex differences in incidence, presumed difference in course of illness, and the identified lack of difference in prevalence warrants closer scrutiny.

    “The lack of coherence between (a) the sex differences found in the incidence of schizophrenia, (b) the presumed difference in course of illness, and (c) the identified lack of difference in prevalence warrants closer scrutiny.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    One in a hundred is an overestimate; the LMR for schizophrenia is between seven and eight per 1,000.

    “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.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [232]

      Not checked in the free run.

    • cites [233]

      Not checked in the free run.

    • The authors state this as an assumption: The oft-quoted statistic that schizophrenia affects about one in a hundred derives from LMR data.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    The authors may have missed studies and/or made data entry errors.

    “Based on our experience with previous systematic reviews, we acknowledge that we may have missed studies and/or made data entry errors.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    In the absence of clear guidelines on how to synthesize descriptive studies, many of the rules used to filter studies and extract data were necessarily ad hoc.

    “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.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [26] Stroup, 2000, JAMA source

      Not checked in the free run.

    • cites [237] von Elm, 2004, BMJ source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    Current treatments fail to cure most patients with schizophrenia.

    “Taken together with estimates on the incidence of schizophrenia (that is, the annual number of new cases), it is also clear that current treatments fail to cure most patients with schizophrenia.”
    Quote in the paperNot a substantial claim
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?

  • Community estimates of schizophrenia are up to 0.8%.

    “up to 0.8% when only schizophrenia is reported [70]”

    From The Prevalence of Mental Disorders among the Homeless in Western Countries: Systematic Review and Meta-Regression Analysis (2008) · cites this paper as [70]

  • Saha et al. systematic review found lifetime morbidity risk of schizophrenia 7.2 per 1,000 persons, with 10% and 90% quantiles 3.1 and 27.1, and huge difference across studies.

    “A systematic review by Saha et al. (2005) found a lifetime morbidity risk of 7.2 per 1,000 persons; the 10% and 90% quantiles were 3.1 and 27.1, respectively.”

    From Excess early mortality in schizophrenia. (2014) · cites this paper as Saha et al. 2005

  • Schizophrenia has very high heritability inferred from twin studies and few replicated GWAS hits despite extensive scans, yet shows demographic influences such as elevated disease rates in children born after migration to cities.

    “Schizophrenia, a disease with very high heritability (inferred from twin studies) and for which very few replicated GWAS hits have been identified despite extensive scans, nevertheless shows such demographic influences as whether the parents live in rural or urban areas (disease rates are elevated in children born after migration to cities)62.”

    From Rare and common variants: twenty arguments (2012) · cites this paper as [62]

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

Cites

Flagged first, then by citations

1 of the 240 references couldn’t be matched to a known paper.

Research works printed but not linked: 53

  1. Larsson, 1954, Acta Psychiatr Neurol Scand, 89, 11
  2. El-Saadi, 2002, Schizophr Res, 53, 32
  3. Bagley, 1969, Race Today, 1, 170
  4. Chattopadhyay, 1989, Indian J Public Health, 33, 37
  5. Chen, 1998, Chin J Psychiatry, 31, 72
  6. Clare, 1974, J Ir Med Assoc, 67, 20
  7. Cooper, 1983, Nervenarzt, 54, 239
  8. Di Marco, 1982, Acta Psiquiat Psicol Amer Lat, 28, 93
  9. Dourado, 2000, Am J Med Gen, 96, 513
  10. Fujita, 1991, Nippon Koshu Eisei Zasshi, 38, 233
  11. Hagnell, 1994, Scand J Soc Med, 50, 1
  12. Helgason, 1977, Acta Psychiatr Scand Suppl, 1
  13. Hinterhuber, 1998, Wien Med Wochenschr, 148, 253
  14. Ichinowatari, 1987, Jpn J Psychiatry Neurol, 41, 629
  15. Junginger, 1993, Hosp Community Psychiatry, 44, 381
  16. Kay, 1989, West Indian Med J, 39, 30
  17. Kracuk, 1965, Zh Nevropatol Psikhiatr Im S S Korsakova, 65, 608
  18. Magzumova, 2001, World J Biol Psychiatry, 2, 203S
  19. Mehta, 1985, Indian J Psychiatry, 27, 153
  20. Moreno-Kustner, 2002, Acta Psychiatr Scand, 105, 24
  21. Murthy, 1978, Indian J Psychiatry, 20, 143
  22. Nandi, 1975, Indian J Psychiatry, 17, 87
  23. Neehall, 1991, West Indian Med J, 40, 16
  24. Nica-Udangiu, 1983, Neurol Psychiatr (Bucur), 21, 115
  25. Nilsson, 1983, J Clin Exp Gerontol, 5, 101
  26. O'Hare, 1972, J Ir Med Assoc, 65, 189
  27. Ouspersicaya, 1978, Zh Nevropatol Psikhiatr Im S S Korsakova, 78, 742
  28. Padmavathi, 1988, Indian J Psychiatry, 30, 233
  29. Pantelis, 1988, Psychiatr Bull R Coll Psychiatr, 12, 98
  30. Pfeiffer, 1974, Confin Psychiatr, 17, 15
  31. Reker, 1997, Gesundheitswesen, 59, 79
  32. Repetto, 1988, Epidemiol Prev, 10, 20
  33. Rin, 1962, J Ment Sci, 108, 134
  34. Sachdeva, 1986, Indian J Psychiatry, 28, 317
  35. Sadoun, 1979, J L'Hopital Sainte-Anne, 5, 1
  36. Salan, 1992, ASEAN J Psychiatry, 2, 52
  37. Satija, 1984, Indian J Psychiatry, 26, 147
  38. Sethi, 1972, Indian J Psychiatry, 14, 183
  39. Sethi, 1972, Indian J Psychiatry, 14, 115
  40. Shah, 1980, Indian J Psychiatry, 22, 384
  41. Shen, 1981, Chin Med J (Engl), 94, 153
  42. Shmaonova, 1983, Zh Nevropatol Psikhiatr Im S S Korsakova, 83, 707
  43. Suzuki, 1990, Nippon Koshu Eisei Zasshi, 37, 991
  44. Tansella, 1991, Psychol Med, 19, 5
  45. Temkov, 1975, Soc Psihijatr, 3, 111
  46. Verghese, 1973, Indian J Med Res, 61, 608
  47. Warthen, 1967, Psychiatr Res Rep Am Psychiatr Assoc, 22, 149
  48. Xia, 1988, Int J Ment Health, 16, 81
  49. Xu, 1991, Chung Hua Shen Ching Ching Shen Ko Tsa Chih, 24, 87
  50. Yang, 1989, Chung Hua Shen Ching Ching Shen Ko Tsa Chih, 22, 366
  51. Yursinova, 1982, Zh Nevropatol Psikhiatr Im S S Korsakova, 9, 93
  52. Murray, 1997, The essentials of postgraduate psychiatry, 3rd ed, 281
  53. Harding, 1987, Hosp Community Psychiatry, 38, 477

Cited by

Sorted by citations

Related

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
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
Licence
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
  • Social Sciences › Psychology › Social Psychology › 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

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-06.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-06.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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