Depression as a Risk Factor of Organic Diseases: An International Integrative Review

PURPOSE AND DESIGN: This integrative review offers a systematic synthesis of the international literature regarding the role of depression as a risk factor in physical illnesses and the mechanisms of this connection. Special attention is paid to those modifiable factors. FINDINGS: Published studies of depression and physical illness and disease(N = 24) from five countries that were indexed in PubMed, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), APA PsycNET, Scopus, Dialnet, and CUIDEN were examined. Results suggest that depression is a significant risk factor for the development of physical illnesses and diseases. More commonly studied were the connections between depression and cardiovascular disease, metabolic syndrome, biochemical alterations, diabetes, dementia, cognitive impairment, Alzheimer's disease, somatization and chronic pain, asthma, arthritis, and hyperlipidemia. Less frequently studied conditions connected to depression were cancer, infections, allergies, autoimmune disease, gastric ulcer, rhinitis, thyroiditis, bronchitis, migraines, fractures, and osteoporosis. CONCLUSIONS: Mechanisms connecting depression to physical illness appear to involve alterations in the hypothalamic-pituitary axis, unhealthy lifestyle, chronic or acute stressors including posttraumatic stress, an increase in C-reactive protein (CRP) in men, taking antidepressant medication, and social and emotional loneliness. CLINICAL RELEVANCE: A good patient-provider relationship can help to promote decreased acute or chronic stressors, increased family and social support, decreased loneliness, modification of unhealthy lifestyles such as smoking, obesity, physical inactivity, alcohol, control of CRP, and antidepressant medication. Nurses are well placed to help prevent physical diseases through detection and referral of patients who are depressed or undiagnosed and not receiving adequate mental health treatment.