Dr Brock Chisholm, the first Director-General of the World Health Organization (WHO), was a psychiatrist and shepherded the notion that mental and physical health were intimately linked. He famously stated that “without mental health there can be no true physical health”.
More and more science is acknowledging the mind-body-spirit connection in physical illness. Norman Cousins, who suffered from ankylosing spondylitis, found that laughter helped him survive long after his initial prognosis of having just a few months to live. (Twenty six years, to be exact.) Therapy can help you discover and heal the trauma and beliefs that may be contributing to illness - newly diagnosed or chronic. It is not meant to be a substitute for medical care, however!
Dr. Lawrence LeShaun studied cancer patients over the course of his entire career, talking with newly diagnosed cancer patients and those with recurrence of their cancers, and found that many had experienced trauma in the past seven years that closely mimicked early childhood trauma (eg loss of a parent, etc.). Psychotherapy with those clients helped many have productive, satisfying lives after their cancer was healed or right up until their deaths from the disease.