novel approach to mind wandering in major depressive disorder and bipolar disorder patients: does the direction of thoughts matter?

Introduction: this study investigated the features of mind wandering in patients with major depressive disorder and bipolar disorder in comparison with the healthy control group.method: 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.results: 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.conclusion: 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.