Is geriatric depression scale a valid instrument to screen depression in Chinese community-dwelling elderly?

BACKGROUND The geriatric depression scale (GDS) is used widely as a screening instrument for depression worldwide. The present study aims to examine the reliability and validity of the GDS with 30 items (GDS-30) in Chinese cognitively normal elderly, and to preliminarily investigate the appropriateness of the GDS-30 among screened mild cognitive impairment (MCI) elderly and among the large-scale community-dwelling Chinese elderly. METHODS A total of 12,610 Chinese elderly completed GDS-30 in the project of Community-based Cohort Study on Nervous System Diseases. Of these, 5503 individuals with the ability to perform basic daily living activities were randomly sampled to further complete the Montreal Cognitive Assessment to screen for MCI. The cutoff value of screened depression was 11, and the cutoff values of MCI were education-dependent. Internal consistency was used to evaluate the reliability. Exploratory factor analysis (EFA) was used to determine the factor structure. Confirmatory factor analysis (CFA) was conducted to assess the construct validity in the elderly screened normal cognition, screened MCI, and the whole population, respectively. RESULTS The Kuder-Richardson coefficient (KR20) was 0.834, 0.821 and 0.840 for the cognitively normal elderly, screened MCI and the whole population, respectively. EFA showed that GDS-30 can be either a four-factor model (named positive mood, dysphoria, worry, and social withdrawal-cognitive impairment) or a two-factor model (named depression and positive mood). The latter was easier to interpret. CFA showed that the two-factor model fitted well in the elderly with normal cognition, with screened MCI, and the whole sample. The factors loaded from 0.900 to 0.588, 0.882 to 0.529, and 0.888 to 0.556 in these three populations respectively. CONCLUSIONS The GDS-30 has good reliability and validity and can be appropriately applied to screen depression in the large-scale community-dwelling Chinese elderly regardless of the presence of mild cognitive impairment.