A systematic review of the prevalence of schizophrenia.
Level 1 - systematic review of randomized trials
Systematic review of observational prevalence studies
PubMed 15916472 · doi:10.1371/journal.pmed.0020141
What was done
Authors conducted a systematic review of original studies published between 1965 and 2002 reporting the prevalence of schizophrenia, identified via database searches, citation reviews, and author contact. Studies were categorized into core, migrant, and other special group studies. Discrete prevalence estimates were analyzed across point, period, lifetime, and lifetime morbid risk metrics, and evaluated against sex, urbanicity, migrant status, country economic index, and study quality score.
What was found
The review identified 188 studies providing 1,721 prevalence estimates across 46 countries, encompassing an estimated 154,140 potentially overlapping cases. Median values per 1,000 persons (10% to 90% quantiles) were 4.6 (1.9 to 10.0) for point prevalence, 3.3 (1.3 to 8.2) for period prevalence, 4.0 (1.6 to 12.1) for lifetime prevalence, and 7.2 (3.1 to 27.1) for lifetime morbid risk. Migrants showed higher prevalence than native-born individuals with a median ratio of 1.8 (10% to 90% quantile 0.9 to 6.4). Prevalence was significantly lower in least developed countries compared to emerging and developed sites (p = 0.04), and higher in studies with higher quality scores (p = 0.02). No significant differences were found between males and females or across urban, rural, and mixed sites.
Why it matters
This review establishes global benchmark ranges for schizophrenia prevalence and demonstrates that prevalence varies substantially by migrant status, national economic index, and methodological quality rather than remaining uniform globally.
Limits
The underlying estimates show wide variation as indicated by broad quantile ranges. Lower prevalence in less developed countries and lower-quality studies suggests potential under-ascertainment or methodological artifacts. The dataset includes potentially overlapping prevalent cases across included studies.
Cited by
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