BACKGROUND: This study aimed to elucidate the validity and reliability of the Korean version of the Mood Disorder Questionnaire (K-MDQ), which is a screening instrument developed for bipolar disorders. METHODS: This study translated the MDQ into Korean to produce the K-MDQ. The K-MDQ was applied to 126 outpatients with bipolar disorder clinically diagnosed by Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition and 112 controls without a psychiatric history. The long-term test-retest reliability with a 10-month interval was investigated in 30 bipolar outpatients. RESULTS: The internal consistency (Cronbach alpha) of the K-MDQ was .88. The correlations between each item and the total score ranged from 0.43 to 0.76 and were all statistically significant (P < .001). Factor analysis revealed 3 factors that explained 59.5% of the total variance. The mean total score was higher in patients (8.48) than in controls (4.51) (P < .001). A total K-MDQ score of at least 7 was chosen as the optimal cutoff, with the 2 parts of the questionnaire on symptoms clustering and functional problems being excluded, since this provided good sensitivity (0.75) and specificity (0.69). The Pearson correlation coefficient for the total test-retest score was 0.63 (P < .001), and the intraclass correlation coefficient was 0.77 (P < .001; 95% confidence interval, 0.52-0.89). CONCLUSIONS: These findings demonstrated the adequate validity and reliability of the K-MDQ, suggesting that this instrument is useful for screening bipolar disorders in Korea. However, we recommend that the original criteria be modified to improve the sensitivity.
BACKGROUND: This study aimed to elucidate the validity and reliability of the Korean version of the Mood Disorder Questionnaire (K-MDQ), which is a screening instrument developed for bipolar disorders. METHODS: This study translated the MDQ into Korean to produce the K-MDQ. The K-MDQ was applied to 126 outpatients with bipolar disorder clinically diagnosed by Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition and 112 controls without a psychiatric history. The long-term test-retest reliability with a 10-month interval was investigated in 30 bipolar outpatients. RESULTS: The internal consistency (Cronbach alpha) of the K-MDQ was .88. The correlations between each item and the total score ranged from 0.43 to 0.76 and were all statistically significant (P < .001). Factor analysis revealed 3 factors that explained 59.5% of the total variance. The mean total score was higher in patients (8.48) than in controls (4.51) (P < .001). A total K-MDQ score of at least 7 was chosen as the optimal cutoff, with the 2 parts of the questionnaire on symptoms clustering and functional problems being excluded, since this provided good sensitivity (0.75) and specificity (0.69). The Pearson correlation coefficient for the total test-retest score was 0.63 (P < .001), and the intraclass correlation coefficient was 0.77 (P < .001; 95% confidence interval, 0.52-0.89). CONCLUSIONS: These findings demonstrated the adequate validity and reliability of the K-MDQ, suggesting that this instrument is useful for screening bipolar disorders in Korea. However, we recommend that the original criteria be modified to improve the sensitivity.