Validation of the Retardation Rating Scale for detecting depression in geriatric inpatients

Validation in the elderly of the Retardation Rating Scale (RRS), which includes items related to motor and mental retardation but not vegetative items, and may be particularly well-suited for the diagnosis of depression in the elderly.

One hundred and sixty-five geriatric inpatients (105 depressed), aged 65 and over, without dementia, neuroleptic medication and increased risk of slowed mobility, were assessed with the RRS and three validated 'gold-standard' scales for geriatric depression (Hamilton Depression Rating Scale, Montgomery and Asberg Depression Rating Scale, Geriatric Depression Scale). Factor analysis used varimax rotation, Cronbach's, Spearman's and Ferguson's coefficients and the Mann-Whitney U-test to evaluate construct and internal consistency. Convergent validity and Receiver Operating Characteristics curves were also analyzed.

Factor analysis retained three interpretable domains: (1) motor items (45% of the variance); (2) mental items and (3) the cognitive items. Internal consistency was high (alpha = 0.91). Each item was strongly correlated with the total RRS score and associated with depression. The RRS showed good convergent validity and its total score increased with depression severity. A cut-off score of 10 yielded 79% sensitivity and 80% specificity, with 80% of the patients properly classified, that is 15% more than standard observer scales.

RRS is a valid screening tool for depression and improves recognition of depression in geriatric inpatients.