Reduced heart rate variability is associated with vulnerability to depression and impaired attentional control to unpleasant affective stimuli

The autonomic nervous system is implicated in cognitive and affective modulation. Heart rate variability (HRV) reflects cardiac autonomic modulation and it is reduced in psychopathology. Dysphoria and remitted depression are conditions of vulnerability to depression. The study investigated whether reduced HRV may represent an indicator of vulnerability to depression and its implication in the association between HRV and attention control of emotional information. Two at‐risk populations [dysphoria (n = 27), remitted depression (n = 16)] and a healthy control group (n = 25) performed an emotional Stroop task (EST) and three‐minute resting‐state ECG. Analysis of covariance was conducted to detect between‐groups differences. Correlation analysis was conducted between response times (RTs) and interference indexes at the EST and HRV. Standard Deviation of Normal to Normal intervals (SDNN) and High Frequency (HF) power of HRV were reduced in both at‐risk groups as compared with controls, whereas no significant effect in the EST was noted. Correlation analysis on the whole sample revealed significant inverse correlations between both HRV parameters and RTs and interference index for unpleasant words. The findings suggest that vulnerability to depression is characterised by reduced vagal tone. In the whole sample, reduced vagal tone was correlated with cognitive‐emotional interference for unpleasant words. Thus, parasympathetic prevalence might facilitate the ability to overcome interference from unpleasant emotional distractors and to direct attention on relevant stimuli.