Development and validation of a screening instrument for bipolar spectrum disorder: The Mood Disorder Questionnaire Thai version

BACKGROUND The Mood Disorder Questionnaire (MDQ) has been translated to many languages and has been used in many countries as a screening instrument for bipolar disorder. The main objective of this study was to evaluate validity of the Thai version of the MDQ as a screening instrument for bipolar disorder in a psychiatric outpatient sample, and to determine its optimum question #1 item threshold value for bipolar disorder. METHODS The English language Mood Disorder Questionnaire (MDQ) was translated into Thai. The process involved back-translation, cross-cultural adaptation, field testing of the prefinal version, as well as final adjustments. Two hundred and fifty major depressive disorder outpatients were further assessed by the Thai version of the MDQ and the Thai version of the Mini International Neuropsychiatric Interview (MINI). During the assessment, reliability and validity analyses, and receiver operating characteristic curve (ROC) analysis were performed. RESULTS The Thai version of the MDQ screening had adequate internal consistency (Cronbach's alpha =0.791, omega total =0.68, and omega hierarchical =0.69). The optimal question #1 item threshold value was at least five positive items, which yielded adequate sensitivity (76.5%), specificity (72.7%), positive predictive value (74.3%), and negative predictive value (75.0%). The ROC area under the curve (AUC) for this study was 0.82 (95% confidence interval: 0.70 to 0.90). CONCLUSION The Thai version of the MDQ had some useful psychometric properties for screening for bipolar disorder in a mood disorder clinic setting, with a recommended question #1 item threshold value of at least five positive items.