Polymorphism | Study | Design | Country | Ancestry* | Participants, n | IQ measure | Mean IQ ± SD | Association between polymorphism and IQ in patients with SSD | ||
---|---|---|---|---|---|---|---|---|---|---|
Patients | Healthy controls | Patients | Healthy controls | |||||||
rs6265† | Ho et al.46 (2006) | Case–control | United States | NA | 293 (SSD) | 144 | WAIS‡ | 91.49 ± 13.49 | 110.41 ± 11.66 | No |
rs6265 | Chung et al.47 (2010) | Case–control | South Korea | East Asian | 101 (schizophrenia) | 50 | WAIS‡ | 102.45 ± 14.1 | 107.9 ± 10.4 | Yes (only before statistical correction) |
rs6265 | Lu et al.48 (2012) | Case–control | China | East Asian | 112 (SSD) | 63 | WAIS‡ | 87.8 ± 14.7 | 113.4 ± 14.2 | Yes |
rs6265 | Smith et al.49 (2012) | Case–control | Canada | 72% Caucasian, 10% South Asian, 9% East Asian, 9% Other | 58 (first episode of psychosis) | 39 | NAART | 100.4 ± 8.7 | NA | No |
rs6265 | Abbasian et al.50 (2021) | Case–control | Iran | Asian | 71 (schizophrenia) | 88 | WAIS‡ | 85.48 ± 13.6 | 98.30 ± 15.12 | No |
NA = not available; NAART = North American Adult Reading Test; SD = standard deviation; SSD = schizophrenia spectrum disorder; WAIS = Wechsler Adult Intelligence Scale.
↵* Terminology taken from the original articles.
↵† rs6265 is commonly known as the Val66Met polymorphism.
↵‡ Patients had significantly lower IQs than healthy controls.