To address the potential confound of group differences in age, identical repeated measures ANOVA were computed for participants falling within a restricted age range of 20–40 years, which formed sample subsets of 40 healthy adults (26.2 ± 5.0 years; 22 female) and 47 schizophrenic patients (27.7 ± 6.0 years; 20 female) with no significant difference in age (F[1, 83] = 2.49, n.s.). These additional analyses yielded almost identical results for both CSD factors (see supplementary Table A). Most importantly, the critical three-way group × condition × task interaction for factor 723 at medial centroparietal, parietal, and occipitoparietal sites was maintained at the same significance level, F(1, 83) = 5.63, p = 0.02.
