Depression is a disorder of the body as much as of the mind. The traditional understanding of pain and depression as separate conditions with overlapping symptoms has evolved through research into an understanding that pain and depression share pathophysiological mechanisms. These shared pathophysiological mechanisms include origins, mechanisms and neurotransmitters, resulting in shared treatments. In addition, pain and depression have a reciprocal relationship in that each heightens the severity of the other. Failure to eliminate the pain symptoms reduces the chances of full recovery from depression: it keeps depressed people from regaining full function in the personal and professional lives, and it raises the danger of suicide. Furthermore, the presence of a depressed mood increases the perception of the severity of, and contributes to distress associated with pain.