Accuracy in detecting major depressive episodes in older adults using the Swedish versions of the GDS-15 and PHQ-9

Objectives: The purpose of this study was to evaluate the diagnostic accuracy at different cut-off values for the Swedish versions of the 15-item Geriatric Depression Scale (GDS-15) and Patient Health Questionnaire (PHQ-9) compared with a structured clinical psychiatric interview in older adults. Methods: Community-dwelling participants (N = 113) aged 65 years or older completed the Swedish versions of the GDS-15 and PHQ-9 and were then interviewed using the Mini International Neuropsychiatric Interview (MINI) to establish the presence or absence of current major depressive episodes (MDEs). Areas under the curve (AUC) were calculated for each scale, as well as the sensitivity, specificity, and Youden's index for different cut-off values. Results: Seventeen participants met the criteria for MDEs. The AUC was 0.97 for the GDS-15 and 0.95 for the PHQ-9. A cut-off of >= 6 on the GDS-15 yielded a sensitivity of 94%, a specificity of 88%, and a Youden's index of 0.82. A cut-off of >= 5 on the PHQ-9 yielded a sensitivity of 100%, a specificity of 81%, and a Youden's index of 0.81. The proposed cut-off of >= 10 on the PHQ-9 produced excellent specificity of 95% but a lower sensitivity of 71%. Conclusions: This study indicates that the Swedish versions of the GDS-15 and PHQ-9 have comparable accuracy as screening instruments for older adults with MDEs. However, the proposed cut-off of 10 on the PHQ-9 might be too high when applied to older individuals in Sweden, and further investigations in larger samples in different healthcare settings are warranted.