Validation of the Depression and Somatic Symptoms Scale by comparison with the Short Form 36 scale among psychiatric outpatients with major depressive disorder.

BACKGROUND: The Depression and Somatic Symptoms Scale (DSSS) is a self-administered scale developed for monitoring both depression and somatic symptoms. The aims of this study were to establish the criterion-related validity of the DSSS by testing the correlation between the DSSS and the Short Form 36 (SF-36) scale and to compare the ability of the DSSS and two other scales in predicting the outcome of the SF-36.
METHODS: The study enrolled 135 outpatients with a major depressive episode, 95 of whom received treatment for 1 month. Four scales were administered and evaluated: the DSSS, the SF-36, the Hospital Anxiety and Depression Scale, and the Hamilton Depression Rating Scale. Pearson correlation was used to test correlations among scales. Multiple linear regressions were used to find the scales most effective in predicting the SF-36.
RESULTS: The three scales were significantly correlated with most of the SF-36 subscales. The depression and somatic subscales of the DSSS significantly correlated with the mental and physical subscales of the SF-36, respectively. The DSSS and the Hospital Anxiety and Depression Scale were better able to predict physical and mental subscales of the SF-36, respectively. The Hamilton Depression Rating Scale had a good ability to predict functional impairment.
CONCLUSIONS: Psychometric scales with appropriate somatic symptoms might be more compatible with both physical and mental dimensions of the SF-36. DSSS proved to be a valid scale for monitoring both depression and somatic symptoms in patients with depression. Future studies should test whether the DSSS is better at predicting the treatment and prognosis of depression than conventional scales for depression. (c) 2009 Wiley-Liss, Inc.