Autonomic Changes Associated with Clinical Depression as Assessed by Short-term Heart Rate Variability (HRV): A Comparative Study

Abstract

Background: In the present scenario, mental health issues have become a global burden. Among all the mental disorders, depression is one of the most disabling and has been a known cardiovascular risk. Autonomic attenuation is put forth as the cause. The literature available on the connection between clinical depression and cardiac autonomic attenuation is limited and inconclusive. Hence, to provide more clarity, with the aid of short-term heart rate variability (HRV), autonomic changes in clinically depressed individuals were assessed.

Methods: Based on the set criteria, we recruited 82 subjects from the hospital's outpatient department after ethical approval. Among them, 41 were depressed individuals, and the rest were non-depressed healthy controls. Depressed individuals were categorized based on their Hamilton scores. Both the groups were subjected to short-term HRV, the measures obtained were compared, and the HRV measures of the depressed individuals were correlated with their Hamilton scores.

Results: HRV measures that reflect cardiovagal activity were found to be significantly less (p = .026) in the depressed individuals. No gender-influenced differences were observed among the depressed. Groups with different levels of depression also revealed no significant differences in their autonomic activity. Hamilton scores of the depressed individuals exhibited no significant correlation with their HRV parameters.

Conclusion: Based on our HRV findings, we conclude that the depressed individuals have reduced cardiovagal activity.

Keywords: Clinical psychology; depression; electrophysiology; neuropsychology.