Table 1.
Demographic and clinical characteristics of the participants
| SZ (N = 174) | HCS (N = 638) | Statistics | |||||
|---|---|---|---|---|---|---|---|
| Mean | SD | Mean | SD | Effect size, d | t or χ2 | p | |
| Age | 34.5 | 11.6 | 33.9 | 12.9 | 0.05 | t (810) = −0.56 | 0.57 |
| Male/female | 98/76 | 315/323 | χ2 (1.0) = 2.64 | 0.10 | |||
| Education (years) | 13.9 | 2.6 | 15.0 | 2.1 | −0.46 | t (810) = 5.78 | 1.1 × 10−8 |
| Premorbid IQa | 102.0 | 10.1 | 108.4 | 7.7 | −0.71 | t (806) = 8.93 | 3.0 × 10−18 |
| Duration of illness (years) | 10.9 | 8.9 | |||||
| PANSS positiveb | 18.9 | 5.7 | |||||
| PANSS negativeb | 20.0 | 5.6 | |||||
| PANSS generalb | 43.3 | 10.7 | |||||
| PANSS totalb | 82.1 | 20.0 | |||||
| Medication | |||||||
| Chlorpromazine equivalent (mg/day) | 581.7 | 519.8 | |||||
| Diazepam equivalent (mg/day) | 8.5 | 28.7 | |||||
| Biperiden equivalent (mg/day) | 0.9 | 1.7 | |||||
Underline indicates p < 0.05
SZ patients with schizophrenia, HCS healthy comparison subjects, SD standard deviation, IQ intelligence quotient, PANSS positive and negative syndrome scale
aN = 170; four patients with schizophrenia have no premorbid IQ data, bN = 173; one patient with schizophrenia has no PANSS data