Model stability of the 15-item Geriatric Depression Scale across cognitive impairment and severe depression

The 15-item Geriatric Depression Scale (GDS) is used in a wide variety of clinical and research settings. The study's purpose was to further establish the validity of the 15-item GDS by exploring the underlying factor structure in a healthy, nondemented sample of older adults and then analyzing whether this factor structure remained stable across a sample of demented individuals and a sample of individuals with a history of depression 6 months after discharge from an inpatient psychiatric setting. A 2-factor model fit the data best in the exploratory analyses. The 2 factors, Life Satisfaction and General Depressive Affect, found in the nondemented sample (r = .39) remained stable across cognitive impairment (r = .12) but merged into a 1-factor model in the psychiatric sample (r = .93). The results indicate that nondepressed older adults with poor life satisfaction may be identified as depressed on screening instruments such as the 15-item GDS.