Figure 1. Cross-validation (5-fold) for the logistic regression classifier of HC vs FENNS-BL groups.
A series of models was chosen by forward selection using as criterion the minimizing of the estimated prediction error (−2 x log likelihood), displayed for each model ± its own standard error. Note that predictors are plasma purine concentrations, only guanine (x = 1) is significant contributor (since its prediction error is within the standard error bar of the 4-variable model, which is the lowest in prediction error). Abbreviations: HC, healthy controls; FENNS-BL, first-episode neuroleptic-naïve schizophrenic patients at baseline.