Development of the Thai Depression Inventory.

The Thai Depression Inventory was developed as a self-rating instrument for measuring the severity of depression. The items used were based on widely used Western scales and on common manifestations and idioms of distress among depressed Thai subjects. The scale was tested with 50 depressed patients using the Hamilton Rating Scale for Depression as an external standard. The internal reliability and concurrent validity were good (Cronbach alpha = 0.858; r = 0.72). The items of psychomotor retardation and loss of libido were poorly correlated with the total score. Factor analysis revealed five distinct factors which accounted for 59.8 per cent of the total variance. Anxiety-insomnia factor was the predominant factor. For major depressive patients, the Thai Depression Inventory total score is 35 or above. The Thai Depression Inventory is a culturally appropriate instrument for measuring the severity of depression with satisfactory reliability and validity.