Table 1.
Demographic, clinical and cognitive characteristics of the studied groups
| Characteristics | SZ (n = 35) M (SD) | HC (n = 35) M (SD) | Statistic value |
|---|---|---|---|
| Age (years) | 21.14 (2.95) | 21.54 (0.70) | F (1, 68) = 0.60, p = 0.438, ηp2 = 0.008 |
| Male/female | 17/18 | 15/20 | χ2 = 0.23, df = 1, p = 0.631 |
| Education (years) | 13.85 (1.86) | 14.20 (1.36) | F (1, 68) = 0.76, p = 0.383, ηp2 = 0.011 |
| Premorbid IQ | 107.60 (6.66) | 107.82 (7.52) | F (1, 68) = 0.06, p = 0.893, ηp2 = 0.001 |
| Duration of illness (months) | 12.31 (5.65) | NA | NA |
| Duration of untreated psychosis (months) | 4.85 (4.79) | NA | NA |
| PANSS positive | 14.34 (4.73) | NA | NA |
| PANSS negative | 19.25 (6.14) | NA | NA |
| PANSS general | 34.87 (6.12) | NA | NA |
| PANSS total | 68.34 (10.53) | NA | NA |
| Risperidone equivalents | 4.37 (1.48) | NA | NA |
| Cognitive speed: | |||
| Total number of processed stimuli | 55.20 (13.16) | 74.20 (7.24) | F(1, 65) = 54.60, p < 0.0001, ηp2 = 0.456b |
| Total number of errors | 3.11 (3.17) | 1.85 (2.39) | F(1, 65) = 3.51, p = 0.065, ηp2 = 0.051b |
| RTmean | 1685.76a (414.15) | 1212.39 (121.16) | F(1, 65) = 41.74, p < 0.0001, ηp2 = 0.381b |
| iSD | 967.09a (599.86) | 602.55 (327.48) | F(1, 65) = 11.19, p = 0.001, ηp2 = 0.146b |
| Ex-Gaussian indicators: | |||
| μ | 990.44a (170.91) | 765.19 (68.91) | F(1, 65) = 51.52, p < 0.0001, ηp2 = 0.442b |
| σ | 78.31a (63.78) | 90.81 (62.52) | F(1, 65) = 1.37, p = 0.244, ηp2 = 0.019b |
| τ | 673.93a (333.09) | 455.23 (143.84) | F(1, 65) = 13.65, p = 0.0004, ηp2 = 0.173b |
Notes: SZ = first-episode schizophrenia patients, HC = healthy controls, PANSS = Positive and Negative Syndrome Scale, assessed during remission phase, NA = not applicable, RTmean = mean reaction time, iSD = individual standard deviation.
aall data given in milliseconds, bANCOVA with age, education and premorbid IQ as controlled covariates.
Bold font indicates statistically significant effects, including Bonferroni correction for multiple testing.