Fig. 2. ROC curves showing model performance in predicting the probability of MDD outcome.

Model 1 consisted of IDS₃₀ total score and Model 2 consisted of six proteins, three sociodemographic factors and three symptoms. The prediction models were applied to predict the probability of MDD outcome in: a the training set (86 first-episode MDD patients vs 86 subthreshold individuals who did not develop MDD within four years), and b the extrapolation test set (37 subthreshold individuals who developed MDD within two or four years vs 86 subthreshold individuals who did not develop MDD within four years). AUC area under the curve, IDS inventory of depressive symptomatology, MDD major depressive disorder, ROC receiver operating characteristic