RRS-4: Short version of the Retardation Rating Scale to screen for depression in elderly inpatients

Objectives: To develop a short version of the Retardation Rating Scale (RRS), an observer scale recently validated in geriatric inpatients. Methods: A neuropsychologist used a structured interview to assess 165 geriatric medical inpatients with the observer-rated Hamilton Depression Rating Scale, Montgomery and Asberg Rating Scale and RRS, and completed the 30-item Geriatric Depression Scale; 107 met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition clinical criteria for depression according to a gerontopsychiatrist's independent evaluation. A statistical model was applied to ascertain the most relevant RRS items; the psychometric properties of the four retained (RRS-4) were compared with standard scales. Results: RRS-4 psychometric properties were good: internal consistency (Cronbach alpha-coefficient = 0.81), positive concurrent validity with each of the standard depression scales (Spearman's r = 0.68-0.82) and the total RRS score (Pearson's r = 0.93). Considering clinical evaluation the "gold standard" for depression, a threshold of three yielded: 88% positive-predictive value, 68% negative-predictive value, with 88% accuracy for predicting depression exceeding the standard observer depression scales by 23%. Conclusion: RRS-4 is a brief and easy-to-use observer scale that improves depression identification in elderly medical inpatients.