Aims: The aim of the present study was to determine the validity of a Chinese version of the Mood Disorder Questionnaire (MDQ) as a screening instrument for bipolar disorder in a psychiatric outpatient population in Hong Kong.
Methods: A total of 185 patients primarily being treated for mood disorders were asked to fill in the Chinese MDQ and supply other personal data during their scheduled clinic visit. The mean age was 43.0 years and 65.9% were female. A subsample of 102 randomly selected subjects, stratified by the MDQ symptom score, received a telephone-based Structured Clinical Interview for DSM-IV (SCID). Sixty-two patients (60.8%) were suffering from bipolar disorder (bipolar I, n = 48; bipolar II, n = 9; bipolar disorder not otherwise specified, n = 5), 35 (34.3%) from depressive disorder, and one (1.0%) from substance dependence, while four (3.9%) were unaffected by either mood or alcohol/substance use disorder. The internal consistency, factor structure and operating characteristics of the Chinese MDQ were analyzed.
Results: The internal consistency of the Chinese MDQ, evaluated using Cronbach alpha, was 0.82. Principal component analysis with varimax rotation indicated an ‘energized-activity’ factor and an ‘irritability-racing thoughts’ factor, which explained 47.2% of the rotated variance. The optimal cut-off was seven or more manic symptoms occurring within the same time period, which yielded a sensitivity of 0.73 and a specificity of 0.88 for detecting bipolar disorder. An additional criterion that the symptoms cause impairment resulted in significant loss of sensitivity.
Conclusion: The Chinese MDQ is a valid screening instrument for bipolar disorder in a psychiatric outpatient population.