Fig. 3. Disease indications of MDD represented by 12 features comprising Model 2.

The distribution of data for individuals in the training set patient group (first-episode MDD patients), the extrapolation test set patient group (subthreshold symptomatic individuals who developed MDD within two or four years), and the shared reference group (subthreshold symptomatic individuals who did not develop MDD within four years) is shown. Protein abundances are represented by the log₂-transformed peptide abundance ratios. The severity of depressive symptoms is represented on scale of 0 (none) to 3 (severe). Numeric features are illustrated using boxplots, and categorical features are illustrated using bar charts