Level of agreement between self-rated and clinician-rated instruments when measuring major depressive disorder in the Thai elderly: a 1-year assessment as part of the THAISAD study

PURPOSE: Whether self-reporting and clinician-rated depression scales correlate well with one another when applied to older adults has not been well studied, particularly among Asian samples. This study aimed to compare the level of agreement among measurements used in assessing major depressive disorder (MDD) among the Thai elderly and the factors associated with the differences found. PATIENTS AND METHODS: This was a prospective, follow-up study of elderly patients diagnosed with MDD and receiving treatment in Thailand. The Mini International Neuropsychiatric Inventory (MINI), 17-item Hamilton Depression Rating Scale (HAMD-17), 30-item Geriatric Depression Scale (GDS-30), 32-item Inventory of Interpersonal Problems scale, Revised Experience of Close Relationships scale, ten-item Perceived Stress Scale (PSS-10), and Multidimensional Scale of Perceived Social Support were used. Follow-up assessments were conducted after 3, 6, 9, and 12 months. RESULTS: Among the 74 patients, the mean age was 68±6.02 years, and 86% had MDD. Regarding the level of agreement found between GDS-30 and MINI, Kappa ranged between 0.17 and 0.55, while for Gwet’s AC1 the range was 0.49 to 0.91. The level of agreement was found to be lowest at baseline, and increased during follow-up visits. The correlation between HAMD-17 and GDS-30 scores was 0.17 (P=0.16) at baseline, then 0.36 to 0.41 in later visits (P<0.01). The PSS-10 score was found to be positively correlated with GDS-30 at baseline, and predicted the level of disagreement found between the clinicians and patients when reporting on MDD. CONCLUSION: The level of agreement between the GDS, MINI, and HAMD was found to be different at baseline when compared to later assessments. Patients who produced a low GDS score were given a high rating by the clinicians. An additional self-reporting tool such as the PSS-10 could, therefore, be used in such under-reporting circumstances.