Recent scientific research suggests that anxiety is the result of a biochemical imbalance in the brain’s alarm center—the amygdala—and a psychological imbalance in thinking. The combination of a biochemically overreactive amygdala and fearful, worrisome thinking causes an exaggerated and persistent stress response. As to which comes first, this is a little like the chicken-or-the-egg question. The answer is both, in a circular pattern of causation. This is the mind-body principle: every change in the mind (anxiety) produces a corresponding change in the body (alarm) and vice versa.