If we were to take an oblique factor through the depression cluster, scores of items on this factor should give us an intensive measure of depression, and likewise a factor through the anxiety cluster should give us an intensive measure of anxiety. The HDS approximates to the depression cluster and appears to be a good extensive measure of severity, but is clearly slightly askew and could be improved upon. It is fairly evident that the HAS could certainly be improved upon as it tends toward the center area. Somewhat surprisingly, the EPI-N and the 16 PF (Q4) appear to be reasonably good measures of anxiety. The numbers of items forming these clusters are variable; nonetheless, they tend to remain stable in the factor space formed by the first two components. We can, however, decide that a smaller rather than greater number of these items could more conveniently describe these clusters and might be a better measure of them. A series of Principal Component Analyses with a decreasing variety of items was undertaken. Each item was assessed visually so that only those that achieved the widest separation across the first and second factor plot and those that also showed contiguity within the separate clusters of anxiety and depressive features were included. It was electively decided to restrict the included items to current mental state and ignore biographical, personality, and other features for purposes of designing purely descriptive psychopathological scales of anxiety and depression; that is, in order to develop descriptive and intensity measures of anxiety and depression, symptom ratings alone were concentrated on in the sequential analysis with the object of deriving the most widely separated items that also remained stable in the factor space. This analysis led eventually to the selection of 26 items as the best replicable descriptive items of the depression and anxiety clusters. These clusters are shown in Fig. 3. This provides some explanation for the difficulties in interpretation posed by the intercorrelations in the literature. It would appear from these analyses that the BDI and ZDS poorly reflect depression in a descriptive sense. They more definitively correlate with the clinical anxiety items. Although they may be of value for rating mood change over time (7), they would appear to be functioning as extensive and not intensive measures of depression or mood in general. It is quite possible, therefore, for them to be sensitive to changes in mood yet not reflect specifically any depressive component. The HAS does not approximate to the center of the anxiety cluster and appears to be a less accurate measure of anxiety than is its counterpart, the HDS, of depression. These two factors are here designated as factor D (depression) and factor A (anxiety) for simplicity. One of the main objectives of this study was to design new rating scales. In this study the actual factor-derived scores of patients are frequently used rather than manipulating numerical scales scores. For application elsewhere, specific scores must be applied to the items comprising each scale. These scales correlate slightly negatively with each other in this population. In other populations selected by different criteria and subject to different selection processes, they might well be independent or positively correlated with each other. Having found these new dimensions that give an accurate mathematical representation of these clusters, we can now see how well the existing scales correlate with these dimensions. Table 6 shows the relative magnitudes of the correlations of the new dimensions or scales compared with the HDS and HAS. This measure of extensive severity is simply the extensive measure of mood referred to earlier, i.e., scores on the general factor. The new anxiety scale and the new depression scale have reason­ably good correlations with this general dimension of mood disorder. The new depression scale correlation is as good as the HDS. The correlations between the two Hamilton scales is 0.55. The new anxiety scale has a high correlation with the HAS and likewise the new depression scale has a high correlation with the HDS, yet their correlations are of a magnitude of -0.19. They are therefore more or less independent, far more so than the existing Hamilton scales. The



generall factor derived from items of the new depression scale has a variance of over 40%. This compares very favorably with the HDS, in which it has been nsistently found to be around 20%, both in this study and the literature. Little has been said here concerning the relationship of these new scales and the established descriptive scales to independent criteria, such as type of treatment allocation, outcome at discharge, or follow-up. Suffice it to say here that the new scales of anxiety and depression were superior at predicting independent treat­ment allocation in the index episode. Further they were better at predicting outcome, at both discharge and over the following year. Rather more importantly, nothing has been said here concerning classification. I will just say this much —if one can isolate truly descriptive and severity measures of the clinical syndromes of anxiety and depression, then one has viable scientific tools with which to address issues of classification. Further, one has useful com­posite, yet unitary, clinical variables to relate to postulated etiological and other factors.
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Anxious Depression: Assessment and Treatment, edited by G. Racagni and E. Smeraldi. Raven Press, New York © 1987.

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