Samira Rostami - Department of Psychology, Allameh Tabataba’i University, Tehran, Iran
Ahmad Borjali - Department of Psychology, Allameh Tabataba’i University, Tehran, Iran
Hossein Eskandari - Department of Psychology, Allameh Tabataba’i University, Tehran, Iran
Reza Rostami - Department of Psychology, University of Tehran, Tehran, Iran
Georg Northoff - Mind, Brain Imaging and Neuroethics, Institute of Mental Health Research, The Royal Mental Health Centre, University of Ottawa, Ottawa, Canada

AbstractIntroduction: 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 ۹۰ 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: ۱) an increased number of internally-oriented thought contents in MDD and BD; ۲) the duration of time MDD and BD groups engage with the internal thoughts is almost twice the time the HC spend on it; ۳) 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.

Keywords: Mind Wandering, Direction of Thoughts, Major depressive disorder, Bipolar Disorder, Internal Thoughts