ABSTRACT
INTRODUCTION It has been emphasized time and again the profound impact that depressive and anxiety disorders may have on patients with chronic medical illness. As depression is often a treatable illness, understanding the prognostic significance of depression in relation to morbidity and mortality is important certainly to each individual patient and from a public health standpoint, as depressive comorbidity often increases societal cost because of health care and disability entitlements, absenteeism, and lost work productivity. It makes intuitive sense, and as you will see throughout this chapter, there is clear evidence that depressive disorders and chronic medical illness can cause increased mortality, morbidity, medical costs, somatic symptoms, problems with adherence to treatment regimens, functional impairment and an overall decrease in quality of life. Major depression has also been shown to adversely affect the habituation process to persistent aversive symptoms such as pain or fatigue, in patients with chronic medical illness that hinders their recovery (1). Multiple studies have reported that patients with depression and anxiety disorders have significantly more unexplained physical symptoms than those without these mental disorders (2). Furthermore, increasing numbers of depression symptoms are associated with increasing numbers of unexplained physical symptoms. In another study, persons younger than 30 years were more depressed, worried, and developed more long-term mental health symptoms than other medically ill age groups (3). Also, patients with depression are less likely to adhere to medication regimens, which is a long-held idea as to the ultimate cause of increased morbidity and mortality in this population.
