Novel Approach to Mind Wandering in Major Depressive Disorder and Bipolar Disorder Patients: Does the Direction of Thoughts Matter?

This study investigated the features of mind wandering in patients with major depressive disorder and bipolar disorder in comparison with the healthy control group.

The number and duration of internally- and externally-oriented thoughts during MW in 90 healthy control, major depressive disorder, and depressed bipolar disorder subjects were measured by a novel method of experience sampling experiment in the laboratory at the Royal Mental Health Centre of the University of Ottawa, Canada using the MATLAB software. Subjects also filled out BDI-II to evaluate current depressive symptoms. The methods used to analyze data included Chi-square, ANOVA, LSD Post Hoc Test, Pearson and Spearman correlation.

1) an increased number of internally-oriented thought contents in MDD and BD; 2) the duration of time MDD and BD groups engage with the internal thoughts is almost twice the time the HC spend on it; 3) the relationship between the direction of thoughts during MW and depressive symptoms.

Our results show depressed patients with MDD and BD spend a longer time on internal thoughts during MW which is related to the severity of their depressive symptoms, which carries clinical implications for both diagnosis and therapy.