Grey matter volume reductions in the emotion network of patients with depression and coronary artery disease

Coronary Artery Disease (CAD) and Major Depressive Disorder (MDD) commonly co-occur and may be linked by a network of brain regions involved in emotion regulation, including the orbitofrontal cortex, amygdala/parahippocamal region and insula. We hypothesized structural differences in this emotion network more prominently in CAD + MDD versus CAD and healthy control (CTRL) groups that do not involve depression-related emotion circuitry. In contrast, we hypothesized structural similarities between CAD + MDD and MDD groups, both involving depression-related circuitry. We obtained structural magnetic resonance imaging scans from age-matched consenting subjects (CAD + MDD, n = 12; CAD, n = 12; MDD, n = 19; CTRL, n = 17) and performed a region of interest analysis. We found decreased grey matter volumes in the bilateral orbitofrontal cortex, bilateral amygdala/parahippocampal gyrus and right insula in CAD + MDD versus CTRL subjects and decreased grey matter volumes in the bilateral amygdala/parahippocampal regions in CAD + MDD versus CAD subjects. We found grey matter reductions in the right orbitofrontal cortex of CAD + MDD versus MDD subjects, and reductions in right insula of CAD versus CRTL subjects. Our results support that the network of brain regions involved in emotion regulation may be relevant to the relationship between CAD and MDD.