Depression - Of the many different mood disorders, depression is the most common, and one of the most misunderstood. While modern research indicates that brain chemical imbalances cause depression, many people still believe that chronic depression indicates a weak personality or character flaw. This makes seeking help for depression difficult, as people hesitate before admitting this 'weakness' to family, friends or doctors. Imagine the devastation and suffering if people hid a major illness such as cancer from the world. When you know more about what's wrong you can make it right.