Assessing Reliability and Validity of the Oxford Depression Questionnaire (ODQ) in a Japanese Clinical Population

Purpose: Originally developed in English, the Oxford Depression Questionnaire (ODQ) is a patient-reported scale specifically developed for assessing emotional blunting in people with major depressive disorder (MDD). We aimed to examine the reliability and validity of the Japanese version of the ODQ.Patients and methods: This was a prespecified analysis of a prospective, 24-week, multicenter, observational cohort study of employed Japanese outpatients with MDD initiating treatment with vortioxetine according to the Japanese label (JRCT1031210200). Participants were assessed using the Japanese version of the ODQ and other clinical rating scales at baseline and Weeks 8, 12 and 24. Results: One hundred and sixteen patients initiated vortioxetine and had >= 1 post-baseline visit. Directionally, the associations between ODQ scores and other clinical measures were as expected and demonstrated good concurrent validity. Factor analysis shows that the scale has a good fit for three factors. The Cronbach's alpha coefficient was 0.912, and the scale also showed good test-retest reliability with intraclass correlation coefficients for the ODQ total score and domains ranging between 0.69 and 0.82. ODQ scores had strong positive correlations with symptom severity assessed using the Montgomery and angstrom sberg Depression Rating Scale and were moderately correlated with work productivity, overall functioning, and quality of life scales.Conclusion: Data from this prospective analysis confirm that the Japanese version of the ODQ retains the good validity and reliability of the original English scale and is suitable for use in prospective studies wanting to capture treatment effects on emotional blunting in MDD.