Demographic, clinical, cognitive and EEG characteristics for each study group*
| Characteristic | Chronic schizophrenia (n = 48) | First-episode schizophrenia (n = 31) | Bipolar disorder (n = 29) | Control (n = 48) |
|---|---|---|---|---|
| Sex, M/F | 29/19 | 19/12 | 17/12 | 26/22 |
| Age, yr | 38.93 ± 9.49 | 30.61 ± 10.14† | 46.40 ± 10.45 | 41.77 ± 8.97 |
| Illness duration, mo | 156.17 ± 115.62 | 23.375 ± 58.70§ | 189.21 ± 106.04 | NA |
| Antipsychotic dose, CPZ eq, mg/d | 447.48 ± 412.95 | 357.40 ± 227.11 | 166.1 ± 155.87‡ | NA |
| Atypical antipsychotic, n | 48 | 31 | 17 | NA |
| Benzodiazepine, n | 20 | 9 | 7 | NA |
| Antidepressant, n | 12 | 4 | 6 | NA |
| Lithium, n | NA | NA | 17 | NA |
| Anticonvulsant, n | NA | NA | 5 | NA |
| Education, yr | 13.71 ± 4.09 | 15.47 ± 3.00 | 15.80 ± 1.78 | 13.20 ± 5.44 |
| Parental education, yr | 11.00 ± 4.51 | 13.21 ± 4.17 | 10.00 ± 2.44 | 9.63 ± 3.92 |
| PANSS positive score | 11.4 ± 4.25 | 10.63 ± 2.77 | 7.36 ± 0.83‡ | NA |
| PANSS negative score | 17.75 ± 8.73 | 14.83 ± 4.22 | 9.05 ± 2.48‡ | NA |
| PANSS total score | 56.07 ± 21.25 | 47.6 ± 11.18 | 30.57 ± 3.32‡ | NA |
| Young Mania Rating Scale score | 0.83 ± 1.91 | 0.22 ± 0.71 | 1.81 ± 1.34 | NA |
| Hamilton Depression Rating Scale score | 5.77 ± 4.29 | 5.91 ± 4.18 | 4.98 ± 3.81 | NA |
| Brief Assessment of Cognition in Schizophrenia score | ||||
| Verbal memory | 32.75 ± 14.87‡ | 37.62 ± 10.57‡ | 36.00 ± 9.25‡ | 48.55 ± 8.53 |
| Working memory | 15.97 ± 4.85‡ | 16.38 ± 4.62‡ | 17.57 ± 4.03‡ | 22.04 ± 3.35 |
| Motor speed | 61.42 ± 21.29‡ | 55.57 ± 15.16‡ | 66.10 ± 13.67‡ | 76.90 ± 13.79 |
| Verbal fluency | 17.37 ± 7.04‡ | 16.79 ± 7.31‡ | 19.78 ± 7.87† | 27.21 ± 7.41 |
| Performance speed | 39.76 ± 15.30‡ | 45.11 ± 13.12‡ | 41.84 ± 12.40‡ | 65.76 ± 14.57 |
| Problem-solving | 16.52 ± 4.60 | 15.24 ± 3.93 | 15.94 ± 3.30 | 17.18 ± 3.23 |
| MSCEIT score | 92.38 ± 23.51‡ | 101.27 ± 18.69‡ | 104.05 ± 22.09‡ | 120.61 ± 22.27 |
| Total IQ | 95.27 ± 14.07‡ | 87.50 ± 14.70‡ | 98.31 ± 10.23‡ | 115.11 ± 10.39 |
| P300 amplitude, mV | 1.04 ± 0.61 | 1.20 ± 0.70 | 1.23 ± 0.63 | 1.58 ± 0.76 |
| P300 latency, ms | 423.22 ± 95.43 | 455.13 ± 87.39 | 464.69 ± 96.11 | 458.54 ± 71.40 |
| Spectral entropy modulation, factor score | 0.198 ± 0.134‡ | 0.067 ± 0.183† | 0.536 ± 0.185§ | −0.345 ± 0.134 |
| Structural small-world index | 0.97 ± 0.01†(n = 21) | 0.98 ± 0.00 (n = 18) | 0.97 ± 0.01† (n = 21) | 0.98 ± 0.00 (n = 20) |
| Structural connectivity strength | 0.31 ± 0.03§ (n = 21) | 0.34 ± 0.01 (n = 18) | 0.30 ± 0.03§ (n = 21) | 0.34 ± 0.03 (n = 20) |
CPZ eq = chlorpromazine equivalent; EEG = electroencephalogram; IQ = intelligence quotient; MSCEIT = Meyer, Salovey and Caruso Emotional Intelligence Test; NA = not applicable; PANSS = Positive and Negative Syndrome Scale.
↵* Spectral entropy modulation values correspond to factor scores from the factor analysis (see text).
Findings are presented as mean ± standard deviation, unless otherwise indicated.
Significant differences with respect to controls are highlighted (†p < 0.05; ‡p < 0.01; §p < 0.001). For PANSS scores, illness duration and treatment doses, differences were calculated between patient groups only.