Dysfunction of External Switching and Backward Inhibition in Major Depressive Disorder：General or Emotional specific?

Abstract

Abstract It remains controversial whether individuals with major depressive disorder (MDD) have dysfunctions in switching and/or inhibition when shifting their attention from one task set to another and whether such dysfunctions, if present, are general or specific to emotional content. In the present study, we investigated these questions with a modified task-switching task to measure the switch cost (the ability to activate a new set) and backward inhibition (the ability to inhibit a task set no longer relevant) in both clinical MDD patients and non-depressive control (NDC) individuals. The dysfunctions were identified to be in the emotional domain. Compared with NDCs, MDDs showed general and emotion-specific dysfunctions in external switching, especially difficulty switching attention from an emotional task to a non-emotional task. Further, this dysfunction was independent of rumination. In contrast, although emotional dysfunction in backward inhibition was also observed in MDD, it was closely related to elevated rumination scores. The results suggest that different symptoms of MDD were associated with different cognitive dysfunctions.