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

Abstract

Abstract The debate continues regarding whether individuals with major depressive disorder (MDD) experience dysfunctions in switching and/or inhibition when shifting their attention from one task set to another and whether such dysfunctions, if they exist, are broad in general or specific to emotional content. This study aims to address these uncertainties by utilizing an adapted task-switching paradigm to evaluate the "switch cost" (the capacity to activate a new task set) and "backward inhibition" (the ability to suppress a task set that has become irrelevant) in both clinical MDD patients and non-depressive control (NDC) individuals. The present findings identified the dysfunctions in MDD were to be in both the general and emotional domain compared with NDC when they performing the external task switching. Especially, MDD encountered challenges when 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 a pattern wherein distinct symptoms of MDD are associated with different cognitive dysfunctions.