Results: Independent analyses of putative SMPI items identified only seven items as required to discriminate
those with clinically-diagnosed melancholic or non-melancholic depression when the conditions were
examined separately. An RPART analysis considering differentiation of melancholic and non-melancholic
depression in the total samples retained five of those items in the classification tree, three of which were
non-symptom items, and with 92% sensitivity and 80% specificity in the development sample. This reduced
item set showed 93% sensitivity and 82% specificity in the validation sample.