Table 4

Studies exploring the TCF4 gene and IQ in patients with schizophrenia

PolymorphismStudyDesignCountryAncestry*Participants, nIQ measureMean IQ ± SDAssociation between polymorphism and IQ in patients with SSD
PatientsHealthy controlsPatientsHealthy controls
rs9960767Lennertz et al.56 (2011)Cross-sectionalGermanyNA401 (schizophrenia)NAMWT-B, WAIS105.28 ± 17.7NANo
rs2958182Zhu et al.57 (2013)Case–controlChinaEast Asian526 (schizophrenia)421WAIS96.01 ± 14.99110.13 ± 11.6Yes
rs9960767Albanna et al.58 (2014)Cross-sectionalCanada103 Caucasian, 70 Other173 (FEP)NAWAIS90.9 ± 15.25NANo
  • 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.