Table 2

Clinical and demographic characteristics of study samples

Group; no. (%)*
CharacteristicStudy sample, cognitive data n = 173Study sample, imaging data n = 82rs1938526 AA n = 147rs1938526 G carrier n = 26
Male sex132 (76)61 (74)119 (80)14 (54)
Age at cognitive testing, mean (range) yr22.8 (16–31)23.7 (18–31)22. (16–31)23. (18–28)
Education, mean (SD) yr11.3 (2.4)11.9 (2.4)11.3 (2.3)10.8 (2.7)
Diagnosis
 Nonaffective psychosis138 (80)69 (84)118 (80)20 (77)
 Schizophrenia102 (59)50 (61)89 (61)13 (50)
 Bipolar disorder24 (14)10 (12)22 (15)2 (8)
Age at onset of psychosis, median (range) yr21.2 (13–31)22.1 (15–31)21.1 (13–31)21.3 (14–27)
White race102 (59)55 (68)90 (61)13 (50)
Cognition tested in mother tongue136 (79)67 (83)120 (82)16 (62)
Lifetime substance-use disorder diagnosis116 (67)53 (65)101 (69)15 (60)
Taking antipsychotics at cognitive testing139 (95)69 (97)114 (94)24 (92)
Chlorpromazine equivalents at cognitive testing, mean (SD)237 (241)210 (185)235 (252)246 (186)
Full scale IQ, mean (SD)92.6 (15.7)95.3 (14.5)94.1 (15.8)84.5 (13.2)
  • SD = standard deviation.

  • * Unless otherwise indicated.

  • p < 0.05.

  • p < 0.01.