Eveningness and Impulsivity in Euthymic Mood States Adversely Affect the Quality of Life of Major Depression and Bipolar Disorder Patients

Objective: Chronotype and impulsivity are important features to be examined in mood disorder patients; these characteristics precede mood disorder onset and persist between mood episodes. Moreover, quality of life is an important outcome in psychiatric patients. This study investigated the interaction between these features and its effect on mood disorder patient’s quality of life.Methods: Early-onset major depressive disorder (MDD), bipolar disorder I (BD I), and bipolar disorder II (BD II) patients were recruited. Excluding 18 patients who were missing data on main variables and 5 patients who were classified as severely ill, a total of 472 euthymic patients (MDD=167, BD I=133, BD II= 172) were assessed on their chronotype, trait impulsivity, and quality of life using self-reports.Results: Both impulsivity and eveningness were negatively associated with quality of life. Regression results showed that there was a significant interaction effect between eveningness and impulsivity on quality of life. This indicates that the higher the level of impulsivity in mood disorder patients, the negative effect of eveningness on quality of life increased.Conclusion: The current study suggests that examination of impulsive personality in relation to chronotype may be important in further understanding the effects of these features on mood disorder patients’ lives.