Autonomic Dysfunction and Depression: A Biomarker of MDD Across the Life Span

Objective: To perform an exploratory review of the association between autonomic function and depressive symptoms/major depressive disorder (MDD) with a particular emphasis on their combined impact on cardiovascular health across the lifespan.

Method: A review of computerized databases was performed using PubMed, Medline, PsycINFO, Scopus, Google Scholar, and BioMed Central from 1950 – 2013. Articles that primarily focused on the association between depression/ MDD and autonomic function, notably cardiovascular health, were included for review. The search was augmented by tracking citations from reference lists of original reports included in the review. Seven hundred and thirty seven articles were screened, 89 articles met criteria for inclusion and 54 articles were incorporated to the current review.

Results: Three large scale epidemiological studies were identified; their results suggest that autonomic dysfunction is consistently present among individuals experiencing depressive symptoms and/or clinically diagnosed with MDD. Moreover, autonomic dysfunction is implicated with elevated risk for cardiovascular disease (CVD) and its associated mortality. Studies have reported that autonomic dysfunction is present in the context of depression (depressive symptoms as well as clinically diagnosed MDD) across the life span with males and females reported to be differentially affected. The role of antidepressants in ameliorating autonomic dysfunction associated with MDD and depressive symptomatology has mixed results.

Conclusion: Autonomic dysfunction is a marker of depression. Autonomic dysfunction can be measured, not only in the laboratory, but also in the clinical ecosystem. Among individuals experiencing depressive symptoms and/or clinically diagnosed MDD, autonomic dysfunction may represent a biomarker for a subpopulation at increased risk of developing CVD.