Chronic pain describes pain that lasts more than three to six months, or beyond the point of tissue healing. Chronic pain is usually less directly related to identifiable tissue damage and structural problems. There are at least two different types of chronic pain problems - chronic pain due to an identifiable pain generator (e.g. an injury), and chronic pain with no identifiable pain generator (e.g. the injury has healed) often termed “chronic benign pain”. Chronic pain and depression are two of the most common health problems that health professionals encounter. The type of depression with chronic pain is referred to as major depression or clinical depression.