Cognitive Therapy is well known for being effective for depression (it's twice as effective as medication in preventing relapse) and it's also been shown to work for many other disorders -- but why? How does it work? A major clue to how Cognitive Therapy affects the brain came out in this study two years ago -- researchers were interested in seeing how Cognitive Behavior Therapy affected the brains of depressed people as compared to medication. They hypothesized that since both CBT and medication were effective for depression, both treatments would affect the same part of the brain. Using brain imaging technology, they scanned participants' brains before and after the course of treatment. And they were in for a surprise. Researchers found that antidepressants affected one part of the brain among depressed patients, and CBT treatment affected another part altogether. Antidepressants dampened activity in the limbic system -- the emotional center of the brain. Conversely, CBT calmed activity in the cortex -- the brain's seat of reason. In other words, antidepressants reduced emotions, whereas CBT helped patients process their emotions in a healthier manner. Which explains why those on antidepressants have a much higher likelihood of relapse if they go off of their meds -- negative emotions can flood back in. But with CBT, patients gain the skills to respond to their emotions more effectively -- for long-term benefits.