Heart rate variability predicts therapy outcome in pain-predominant multisomatoform disorder

Background: Autonomic imbalance establishes an important model to understand organically unexplained physical complaints. Our study aimed to investigate whether the functioning of the autonomous nervous system corresponds with somatoform symptoms and predicts the outcome of brief psychotherapy in these patients.

Method: As a part of multicenter study assessing effects of brief psychodynamic interpersonal therapy on multisomatoform disorder (PISO-study), 106 patients participated in a stress experiment investigating autonomic reactivity during application of the Stroop-test. Patients were randomized receiving either enhanced medical care (EMC, N=49) or psychotherapy (N=57). Autonomic baseline functioning as well as stress reactivity of heart rate (HR) and heart rate variability (HRV) were analyzed in their relation to symptom measures and as potential predictors of the primary outcome (Physical Component Score of the SF-36) during 9-month follow-up.

Results: After therapy patients markedly and sustainably improved in physical quality of life, and this long-term improvement was predicted by baseline HR and HRV. HRV also predicted change in pain symptoms following psychotherapy. A responder analysis revealed a significant better treatment outcome in patients with high pre-treatment HRV (OR 3.4, CI: 1.2-9.9, p=.0035). No significant associations between HR or HRV and outcome measures were found in the EMC group.

Conclusion: In our study, the adaptability of the autonomous nervous system as indicated by low pretreatment HR and high HRV was associated with a more pronounced benefit from psychotherapy. This finding can be explained by a possible association between autonomic self-regulation and emotional learning capacities.