Concordant factors of depression rating scales and dimensionality of depression

A redundancy analysis was carried out between a doctor rating scale (D-RS) and a patient self-rating scale (P-SRS) to determine relating dimensions. The first and second major redundancy variates obtained from the P-SRS and the D-RS were rotated to obtain biorthogonality and interpretability. The obtained two concordant dimensions between the P-SRS and the D-RS were interpreted as depression and vegetative factors. Any redundancy factors before the rotations, however, did not reveal a general factor pattern. These results suggest that the two-dimensional structure is more appropriate for understanding the depression symptomatology rather than the unidimensional structure of a general or endogenous factor pattern. We also discussed how dimensional differences caused a low concordance in severity or total scores.