Studies exploring the TCF4 gene and IQ in patients with schizophrenia
| 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 | |||||||
| rs9960767 | Lennertz et al.56 (2011) | Cross-sectional | Germany | NA | 401 (schizophrenia) | NA | MWT-B, WAIS | 105.28 ± 17.7 | NA | No |
| rs2958182 | Zhu et al.57 (2013) | Case–control | China | East Asian | 526 (schizophrenia) | 421 | WAIS† | 96.01 ± 14.99 | 110.13 ± 11.6 | Yes |
| rs9960767 | Albanna et al.58 (2014) | Cross-sectional | Canada | 103 Caucasian, 70 Other | 173 (FEP) | NA | WAIS | 90.9 ± 15.25 | NA | No |
FEP = first episode of psychosis; MWT-B = Mehrfachwahl-Wortschatz Test B; NA = not available; SD = standard deviation; SSD = schizophrenia spectrum disorder; WAIS = Wechsler Adult Intelligence Scale.
↵* Terminology taken from the original articles.
↵† Patients had significantly lower IQs than healthy controls.