Background: Primary care patients with anxiety and depression often describe multiple physical symptoms, but no systematic review has studied the effect of anxiety and depressive comorbidity in patients with chronic medical illnesses.
Methods: MEDLINE databases were searched from 1966 through 2006 using the combined search terms diabetes, coronary artery disease (CAD), congestive heart failure (CHF), asthma, COPD, osteoarthritis (OA), rheumatoid arthritis (RA), with depression, anxiety and symptoms. Cross-sectional and longitudinal studies with >100 patients were included as were all randomized controlled trials that measure the impact of improving anxiety and depressive symptoms on medical symptom outcomes.
Results: Thirty-one studies involving 16,922 patients met our inclusion criteria. Patients with chronic medical illness and comorbid depression or anxiety compared to those with chronic medical illness alone reported significantly higher numbers of medical symptoms when controlling for severity of medical disorder. Across the four categories of common medical disorders examined (diabetes, pulmonary disease, heart disease, arthritis), somatic symptoms were at least as strongly associated with depression and anxiety as were objective physiologic measures. Two treatment studies also showed that improvement in depression outcome was associated with decreased somatic symptoms without improvement in physiologic measures.
Conclusions: Accurate diagnosis of comorbid depressive and anxiety disorders in patients with chronic medical illness is essential in understanding the cause and in optimizing the management of somatic symptom burden.