Cornell's Depression for Dementia Scale : A psychometric study among Norwegian nursing home residents

Background : Depression is common among residents in long term-care facilities. Therefore, access to a valid and reliable measure of depressive symptoms among nursing home (NH) residents is highly warranted. Aim : The aim of this study was to test the psychometrical properties of the Norwegian version of the Cornell Scale for Depression in Dementia (CSDD). Methods : A sample of 309 NH residents were assessed for depressive symptoms using the CSDD in 2015-2016. Data on CSDD were missing for 64 residents, giving an effective sample of 245 (79.3%). Principal component and confirmatory factor analysis were used. Results : A five-dimensional solution yielded the best fit with the data (χ2=174.927, df=94, χ2/df=1.86, p=0.0001, RMSEA=0.058, p-value for test of close fit=0.152, CFI=0.94, TLI=0.92 and SRMR=0.056). As expected, higher depressive symptoms correlated positively with higher scores on the Minimum Data Set Depression Rating Scale (MDSDRS) and correlated negatively with Quality of life assessed with the Quality of Life in Late Stage-Dementia Scale. Limitations : The excluded residents (n=64, 20.7%) had lower cognitive function, which may limit the generalizability of the study results. Conclusion : This study suggests a five-dimensional solution of the CSDD scale. Sixteen of the 19 original items showed highly significant loadings, explaining a notable amount of the variation in the CSDD-construct. Further development and testing of a well-adapted scale assessing depression in the nursing home population with and without dementia is required.