Reduced heart rate variability is associated with vulnerability to depression

Background: Heart rate variability (HRV) mirrors cardiac autonomic modulation, an index of well-being. Reduced HRV has been reported in depression, but few studies investigated HRV in individuals at-risk of or remitted from a full-blown depressive episode. The present study aimed at examining whether reduced HRV could be a potential indicator of vulnerability to depression. Methods: Self-reported psychological measures and three-minute resting-state ECG were collected in two at-risk populations [group with dysphoria (n = 27), group with past depression (n = 16)] and in a control group (n = 25). Time- and frequency-domain HRV parameters were computed. Analysis of covariance was conducted to detect between-groups differences for each measure. Results: Standard Deviation of Normal to Normal intervals (SDNN) and High Frequency (HF) power of HRV were found to be reduced both in individuals with dysphoria and in those with past depression as compared with controls. Whereas psychological measures did not significantly differ among individuals with past depression and controls, HRV was capable of discriminating between the two groups. Limitations: Past depression was assessed retrospectively with self-reported information. The inclusion of a group with depression would provide an overview about HRV during the illness course. Conclusions: The findings suggest that reduced HRV is likely to be implicated in the risk of developing full-blown depression, rather than being a mere correlate of current depressive state. The results suggest that HRV may improve the ability to early identify people at risk for depression who can benefit from targeted prevention by psychiatric and psychological interventions.