The Carroll rating scale for depression. II. Factor analyses of the feature profiles.

Factor analyses were conducted for the Hamilton depression rating scale (HRS) and the self administered Carroll counterpart (CRS). The factor loadings for the respective first factors were similar; those for the respective second factors showed strict sign consistency but only moderate consistency of magnitude; the loadings for the respective third factors showed no particular consistency. The first three CRS and first three HRS factor scores were computed for each individual and correlations were computed from these factor scores. The first and second factors were highly correlated but the third factors were negatively correlated indicating that they were not measuring the same thing. The first factors of the CRS and HRS correlated highly with their respective raw total scores and were indices of the severity of illness. The self-administered CRS (with matching weights) is a credible alternative to the HRS for routine clinical assessment of the severity of depression.