A Preliminary Study on Standardization of Korean Form of Geriatric Depression Scale(KGDS)

Jung, In Kwa; Kwak, Dong Il; Joe, Sook Haeng; Lee, Hyeon Soo

Abstract

The purpose of this study was to construct Korean Geriatric Depression Scale(KGDS) items and test the reliability and validity of KGDS. Total 151 items from GDS, BDI, SDS, MMPI-D, and K-CES-D were administered to 81 depressed elderly and 75 elderly control groups. Sixty-four preliminary items which have discrimination power between depression and control groups were selected. Then by correlational analysis considering adjusted item-total correlation, 40 items were finally chosen to construct KGDS. The values of Cronbach's alpha and split-half reliability were 0.88 and 0.79, respectively. The differences of means was signified at alpha=.001 level(patients group mean=23.40+/-8.13, control group mean=12.50+/-8.82, t=9.76). The result of factor analysis showed that KGDS had six factors. They were labeled negative thinking and unhappiness feeling(factor 1), emotional discomfort(factor 2), cognitive dysfunction(factor 3), decreased vitality(factor 4), physical weakening and inclosed somatic concern(factor 5), social withdrawal and loss of interest(factor 6), which represent depressive features of the elderly in thought, emotional, cognitive, physical, and social aspects. The total percentage of variance of the 6 factors was 51.2%. The result of discrimination analysis showed that hit ratio of KGDS was 76.7%, and the score of 16 was suggested as the optimal cut-off score. Additionally, by using percentile score distribution of control(normal) group, it is suggested that the score of 16-22 represents borderline or mild depression, the score of 23-25 are moderate depression, and greater than the score of 26 severe depression. Conclusively, KGDS not only improves diagnostic discrimination power 10% more than other depression scales including GDS, but also show sufficient reliability and validity, thus can be used for evaluaion of elderly depression. Finally, some issues relevant to sample selection and the necessity of concising content and items of KGDS are discussed.