Development and Validation of the Mood Instability Questionnaire-Trait (MIQ-T)

• Main Authors: Joohyun Yoon, Tae Hyon Ha, Sunghee Oh, Yun Seong Park, Hyun A. Ryoo, Hyeon-A Yu, Seok Joo Hong, Nayoung Cho, Chan Woo Lee, Yoonjeong Jang, Wonyun Lee, Ye Rim Kim, Kwang Ho Park, Jiung Park, Ji Yoon Park, Woojae Myung
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Medicina
• Subjects: mood instability; exploratory factor analysis; scale development; depression; bipolar disorder
• Online Access: https://www.mdpi.com/1648-9144/57/8/838

<i>Background and objectives</i>: Mood instability (MI) is a stable trait associated with psychiatric disorders, yet there is a lack of tools to measure MI. The purpose of this study was to develop and validate the Mood Instability Questionnaire-Trait (MIQ-T) to evaluate MI in mood disorder patients. <i>Material and methods</i>: Items were taken from various established questionnaires to create an initial list of MIQ-T questions. Data from 309 psychiatric patients (<i>n</i> = 309; 62 major depressive disorder, 58 bipolar I disorder, and 189 bipolar II disorder) were gathered from their medical records and were utilized in an exploratory factor analysis to clarify the underlying components of MI. Then, anonymous survey data from 288 individuals from the general population were included in the analysis as a comparison group. Associations between MIQ-T and other previously validated clinical instruments for mood disorders were examined to test external validity. <i>Results</i>: The exploratory factor analysis demonstrated that the five-factor structure (Lability, Upward Tendency, Downward Tendency, Childhood Instability, and Seasonality) of 59 items was the most appropriate with clear, cohesive features. MIQ-T exhibited high internal consistency (α = 0.96) and moderate to strong correlations with other previously validated clinical instruments, which were consistent with theoretical predictions, providing evidence of criterion validity. Short forms were also created to address the high internal consistency value, which can indicate redundancy, and to increase the approachability of the measure. We found that the patients with bipolar II disorder had higher MIQ-T scores than the patients with bipolar I disorder or major depressive disorder and the comparison group. <i>Conclusion</i>: Together, these findings validate the newly developed MIQ-T as an instrument of mood instability. MIQ-T can be a potential research tool for mood disorder.