Researchers have found that people with difficult-to-treat major depressive disorder who show lower activation of the amygdala — a part of the brain involved in processing emotions — when viewing sad versus happy faces are less likely to experience improvement in their depressive symptoms after four months of standard treatment. This discovery, published in the journal Psychological Medicine, could help in developing personalized treatment plans for patients with depression by identifying those less likely to respond to conventional therapies. Only about half of patients with depression respon…