Associations between symptoms of depression and heart rate variability: An exploratory study.

Major depressive disorder (MDD) is associated with decreased heart rate variability (HRV), a predictor of cardiovascular morbidity by many, but not all studies. This inconsistency could be due to the association of HRV with specific depressive symptoms. Here, we investigated the association of HRV parameters with components of depressive symptoms from 120 MDD patients, at baseline of a published trial comparing the effect of sertraline to transcranial direct current stimulation. We used Principal Component Analysis to extract components of the Hamilton Rating Scale for Depression (HAM-D-17), the Montgomery Asberg Depression Rating Scale (MADRS) and the Beck Inventory for Depressive Symptomatology (BDI). We constructed one equation of multiple linear regression for each HRV parameter as the dependent variable, and the components of depressive symptoms of the three scales as the independent ones, adjusted for age and gender. A component of HAM-D-17 predicted LF/HF (low frequency/high frequency) and a component of MADRS predicted LF (low frequency). "Guilt" and "loss of interest/pleasure in activities" were present in the components of both scales, and the MADRS component also included "psychomotor retardation". These results suggest that melancholic features might be relevant for the association between MDD and HRV. Considering multiple comparisons, these results are preliminary.