Depression and Chronic Diseases

OBJECTIVE: To identify the growing significance of depression as a global leading cause of years lost to disability and its role as a major independent risk factor in many chronic illnesses. The distinct effects of depression on morbidity and mortality in cancer, diabetes, heart disease, and stroke are investigated, including behavioral factors and plausible biological mechanisms (psychoneuroimmunology of depression). DATA SOURCES: PubMed articles in English were searched from 1992 to 2012 (20-year span) using the following search criteria: psychoneuroimmunology of depression, immune-mediated inflammation, depression treatment recommendations, depression screening, years lost to disability, underserved populations and depression, chronic illnesses and depression, and selective serotonin reuptake inhibitors and immune system. DATA SYNTHESIS: Evidence of the robust bidirectional relationship between depression and individual chronic diseases is presented and discussed. A brief overview of currently recommended psychotherapeutic and psychopharmacologic treatment approaches in regard to depression in chronic diseases is provided. RESULTS: Discordance between mental health and primary care within the US public health system is a systematic problem that must be addressed. This situation leads to a potentially high hidden prevalence of underdiagnosed and undertreated depression, especially in the underserved populations. CONCLUSION: Measures must be implemented across the communities of mental health and primary care practitioners in order to achieve a synergistic approach to depression.