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Table 1 Characteristics of the 65 included studies

From: An evaluation of variation in published estimates of schizophrenia prevalence from 1990─2013: a systematic literature review

Characteristic Europe Asia North America Africa Oceania All Regions
Number of studiesa 29 13 10 8 4 65
Sample size       
 <5000 3 (10.3 %) 1 (7.7 %) 0 2 (25.0 %) 1 (25.0 %) 7 (10.8 %)
 5000–9999 3 (10.3 %) 4 (30.8 %) 1 (10.0 %) 0 1 (25.0 %) 9 (13.8 %)
 10,000–49,999 6 (20.7 %) 2 (15.4 %) 1 (10.0 %) 4 (50.0 %) 1 (25.0 %) 14 (21.5 %)
 50,000–99,999 4 (13.8 %) 1 (7.7 %) 0 2 (25.0 %) 0 7 (10.8 %)
 100,000+ 13 (44.8 %) 5 (38.5 %) 8 (80.0 %) 0 1 (25.0 %) 28 (43.1 %)
Study design       
 Cohort 16 (55.2 %) 4 (30.8 %) 8 (80.0 %) 0 4 (100 %) 32 (49.2 %)
 Cross-sectional 13 (44.8 %) 9 (69.2 %) 2 (20.0 %) 8 (100 %) 0 33 (50.8 %)
Publication date       
 1990–2002 17 (58.6 %) 2 (15.4 %) 2 (20.0 %) 5 (62.5 %) 2 (50.0 %) 28 (43.1 %)
 2003–2013 12 (41.4 %) 11 (84.6 %) 8 (80.0 %) 3 (37.5 %) 2 (50.0 %) 37 (56.9 %)
Assessment yearb       
 <1990 10 (34.5 %) 1 (7.7 %) 0 2 (25.0 %) 0 13 (20.0 %)
 1990–1999 10 (34.5 %) 3 (23.1 %) 4 (40.0 %) 4 (50.0 %) 2 (50.0 %) 23 (35.4 %)
 2000–2009 7 (24.1 %) 9 (69.2 %) 6 (60.0 %) 1 (12.5 %) 1 (25.0 %) 25 (38.5 %)
 Not reported 2 (6.9 %) 0 0 1 (12.5 %) 1 (25.0 %) 4 (6.2 %)
Prevalence period typec       
 Point 6 (20.7 %) 4 (30.8 %) 1 (10.0 %) 2 (25.0 %) 1 (25.0 %) 14 (21.5 %)
 12 months 11 (37.9 %) 4 (30.8 %) 5 (50.0 %) 1 (12.5 %) 1 (25.0 %) 22 (33.8 %)
 Other period 7 (24.1 %) 2 (15.4 %) 2 (20.0 %) 2 (25.0 %) 0 13 (20.0 %)
 Lifetime 13 (44.8 %) 6 (46.2 %) 3 (30.0 %) 5 (62.5 %) 2 (50.0 %) 30 (46.2 %)
Quality score       
 Mean ± SD 9.0 ± 2.6 8.8 ± 3.4 7.7 ± 2.1 10.1 ± 1.6 8.8 ± 1.5 8.8 ± 2.6
  1. aOne study (Nuevo et al.) reported on multiple regions, and is counted only in the “All regions” category. Therefore, the number of studies in each region sum to only 64 studies
  2. bFor studies that assessed prevalence over a range of years, the most recent year was used
  3. cMultiple types of prevalence could be reported within the same study; therefore, percents do not add up to 100