Reduced emotional and cardiovascular reactivity to emotionally evocative stimuli in major depressive disorder.

Major Depressive Disorder (MDD) is a highly debilitating mental health concern that affects a large number of adults in the United States. The emotional context insensitivity (ECI) hypothesis argues that individuals with MDD disengage from the environment to defend themselves from futile activity. In the current study, electrocardiogram and pupillometry were recorded from 50 participants (MDD n=25, never depressed control n=25) during the display of emotionally evocative images, sounds, and movie clips. Individuals with MDD reported reduced change in happiness to positively- and negatively-valenced images and sounds. Heart rate reactivity also was reduced in individuals with MDD when viewing images and watching movie clips. These results suggest that individuals with MDD may have some difficulty engaging with certain environmental stimuli.