The effects of cognitive-behavioural therapy (CBT) on heart rate variability (HRV) in people with depression and/or anxiety disorders: A systematic review and meta-analysis

Introduction Cognitive-behavioural therapy (CBT) is a widely used intervention for depression and anxiety. However, its effectiveness is typically evaluated using subjective self-report symptom scales, which are susceptible to bias. It is hypothesised that improvements in clinical symptoms following CBT may be accompanied by improvements in physiological regulation, particularly heart rate variability (HRV), which has been proposed as a marker of emotion regulation. We conducted a systematic review with meta-analysis to examine the effects of CBT on HRV in adults with depression and/or anxiety disorders. Methods Following a pre-registered protocol (PROSPERO: CRD420251040957), we searched Embase, PsycINFO, PubMed, and Web of Science for randomised controlled trials (RCTs) and non-randomised interventional studies involving adults with depression and/or anxiety in CBT, and reporting HRV before and after the intervention. Random-effects meta-analyses in R estimated pooled effect sizes (Hedges' g). Results After screening 9713 records, we identified 12 studies; 5 RCTs were included in the meta-analysis, and the remaining 7 in the narrative review because they did not provide calculable effect sizes. Meta-analysis results found that adults randomised to CBT had significantly greater pre-to-post intervention increases in HF-HRV, LF-HRV, and SDNN-HRV. No significant changes were observed for the LF/HF ratio, RMSSD-HRV, and the HRV Triangular Index. Conclusion Our meta-analysis provides emerging evidence that CBT might significantly increase selected HRV indices, suggesting that physiological changes may accompany improvements in psychological symptoms. However, further high-quality research is needed to determine the clinical utility of HRV as a predictor of treatment response and a biomarker for treatment effectiveness.