Depression is associated with increased sensitivity to signals of disgust: a functional magnetic resonance imaging study.

Emotions of fear and disgust are related to core symptoms of depression. The neurobiological mechanisms of these associations are poorly understood. This functional magnetic resonance imaging study aimed at examining the Blood oxygenation level dependent (BOLD) response to facial expressions of fear and disgust in patients with major depressive disorder. Nine patients in an episode of major depression and nine healthy controls underwent two functional magnetic resonance imaging experiments where they judged the gender of facial identities displaying different degrees (mild, strong) of fear or disgust, intermixed with non-emotional faces. Compared with healthy controls, patients with depression demonstrated greater activation in left insula, left orbito-frontal gyrus, left middle/inferior temporal gyrus, and right middle/inferior temporal gyrus to expressions of strong disgust. Depressed patients also demonstrated reduced activation in left inferior parietal lobe to mildly fearful faces. Enhanced activation to facial expressions of disgust may reflect an emotion processing bias that suggests high relevance of emotion of disgust to depression.