Performance of the Hamilton Depression Rating Scale in depressed patients in the United Arab Emirates.

Cross-cultural variation in the frequencies and modes of expression of depressive symptoms may influence the validity of depression rating scales. The most widely used instrument for this purpose, namely Hamilton's Depression Rating Scale (HDRS), has not been systematically evaluated in Arab countries. This study evaluates the face validity of the HDRS-21 by studying symptom frequencies, factor structure and symptom clusters in 100 UAE depressed patients. Concurrent validity is tested by comparing total HDRS scores with global estimates of severity made by clinicians, admission status, impairment of social and occupational functioning, and the endogenicity score of the Newcastle (NC) Diagnostic Index. Total HDRS scores show highly significant agreement with three independent measures of severity of depression. Rank orders of the most and least frequent symptoms are consistent with studies of similar design. Marked differences lie in more retardation and somatization and fewer cognitive components in the present study. Principal-component analysis confirmed the heterogeneous structure of the scale, separating a group of core depressive symptoms, and endogenous, somatization, anxiety and psychotic symptom components. The internal consistency (reliability) of the whole scale is moderate, and improves in the core symptom factor. The main conclusion is that the HDRS is sensitive to severity of depression in the UAE culture. However, it measures heterogeneous aspects, and its internal consistency suffers as a result. High levels of retardation and somatization contribute significantly to the total score in socially developing communities.