MedicalResearch.com Interview with:
Viola Vaccarino, MD, PhD
Department of Epidemiology and Division of Cardiology
Professor, Department of Medicine
Emory University School of Medicine
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Previous studies have shown that people with depression tend to have lower heart rate variability (HRV), an index of autonomic nervous system dysregulation derived by monitoring the electrocardiogram over time, usually for 24 hours. Other literature, however, has pointed out that autonomic dysregulation (as indexed by reduced HRV) may also cause depression. Thus, the direction of the association between reduced HRV and depression still remains unclear. In addition, these two characteristics could share common pathophysiology, making shared familial background and genetic factors potential determinants of this association.
MedicalResearch.com: What are the main findings? What should readers take away from your report?
Response: In a prospective study of twin pairs, we found a consistent and robust association between reduced heart rate variability at baseline and the development or worsening of depression at follow-up, which was not explained by other characteristics of study participants. There was also an association in the opposite direction, linking depression at baseline to worsening of HRV at follow-up, but it was largely explained by antidepressant use.
iOur findings suggest that there is a bi-directional association between depression and autonomic dysregulation, indexed by HRV, with stronger evidence suggesting that autonomic function affects depression risk rather than vice versa. Our results suggest that the autonomic nervous system plays a role in the etiology of depression.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: Future research should evaluate the value of heart rate variability, or other measures of autonomic dysregulation, as biomarkers of depression risk to identify individuals at higher risk for depression or its recurrence or severity. Our results may also inform future research on the evaluation of interventions that modulate autonomic nervous system regulation to prevent and treat depression and its consequences.
MedicalResearch.com: Is there anything else you would like to add?
Response: Rather than common underlying pathophysiology, our twin study suggests a possible causal relationship linking autonomic nervous system dysfunction to depression. This pathway of risk may also be informative in explaining the well-known comorbidity between depression and cardiovascular disease.
MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.
Huang M, Shah A, Su S, et al. Association of Depressive Symptoms and Heart Rate Variability in Vietnam War–Era Twins A Longitudinal Twin Difference Study. JAMA Psychiatry. Published online May 16, 2018. doi:10.1001/jamapsychiatry.2018.0747
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