Baseline Depressive Symptoms and Heart Rate Variability Indices Predict HRV Biofeedback Outcomes in Young Adults with...

Heart rate variability biofeedback (HRVB) has been confirmed to enhance cardiovagal activation and alleviate depressive symptoms in patients with major depressive disorder (MDD). However, it remains unknown which dimensions of depression predict better treatment outcomes following HRVB. This study utilized a randomized controlled trial design. A total of 59 patients with depressive disorder were enrolled and randomly assigned to either the HRVB group or the relaxation training (RT) group. Both groups receive 60-min training sessions twice weekly for 10 sessions over five weeks. Psychological variables (depression and anxiety) and lead II electrocardiogram (ECG) were collected at pre-test and post-test. ECG data were converted into HRV indices. Two-way mixed-design analyses of variances were conducted to examine the Group (HRVB vs. RT) × Time (pre-test vs. post-test transfer) interaction effects on psychological outcomes and HRV indices. In addition, participants in the HRVB group were classified as responders (n = 10) or non-responders (n = 14) based on change in the root mean square of successive differences between normal heartbeats (RMSSD) following HRVB. Differences in demographic and psychological variables between these subgroups were further examined. (1) Both groups showed significant reductions in depression and anxiety over time; however, no significant differences between groups were observed. (2) At the transfer stage, the HRVB group demonstrated significant increases in HRV indices from pre-test rest stage to post-test transfer stage. (3) Within the HRVB group, responders exhibited significantly lower levels of depressive symptoms (including loss of pleasure, loss of interest, worthlessness, and loss of energy) and lower parasympathetic activity compared with non-responders. HRVB not only alleviated depression and anxiety symptoms but also enhanced autonomic nervous system activity. Moreover, patients who derived the greatest benefit from HRVB tended to exhibit more favorable psychological features at pre-test. These findings may inform the development of personalized and evidence-based psychological interventions for patients with depressive disorders.