Development and Validation of a Short Version of the Cornell Scale for Depression in Dementia for Screening Residents in Nursing Homes

Objectives To develop and validate a short version of the Cornell Scale for Depression in Dementia (CSDD-19) for routine detection of depression in nursing homes. Setting Australian nursing homes. Methods A series of cross-sectional studies were conducted involving: 1) descriptive analysis of pooled data from five nursing home studies that used the CSDD-19 (N = 671) to identify patterns of responses and missing data on individual CSDD items; 2) analysis of four of the five studies (N = 556) to assess CSDD-19 for unidimensionality, item fit, and differential item functioning using Rasch modeling to develop a shorter version, the CSDD-4; 3) validation of the CSDD-4 against the DSM-IV using the fifth study of 115 residents and through expert consultations; and 4) evaluation of the clinical utility of CSDD-4 using an independent cohort of 92 nursing home residents. Results Four items from the original CSDD-19 were found to be most suitable for depression screening: anxiety, sadness, lack of reactivity to pleasant events, and irritability. The CSDD-4 highly correlated with the original scale (N = 474, r = 0.831, p