Is respiratory sinus arrhythmia a modifiable index of symptom change in cognitive behavioral therapy for youth? A pooled-data analysis of a randomized trial.

OBJECTIVE: We evaluated whether respiratory sinus arrhythmia (RSA) reactivity and resting RSA-physiological markers reflecting the increase in heart rate with inspiration and decrease during expiration related to parasympathetic influence on the heart-are modifiable and predict symptom change during youth psychotherapy. Methods: Diverse youth ( N  = 158; ages 7-15; 48.1% female) received the Modular Approach to Therapy for Children and completed pre-treatment (pre), post-treatment (post), and 18-months postbaseline (18Mo) assessments. We measured resting RSA, RSA reactivity during stress induction, and psychopathology symptoms. Results: Pre-to-post and pre-to-18Mo, reactivity decreased, and resting RSA increased. Changes in reactivity and resting RSA, separately, did not predict reduced psychopathology. Yet, decreased reactivity combined with increased resting RSA predicted reduced psychopathology over time, suggesting that observed RSA changes were beneficial for some. Higher dosage of a module utilizing slow-breathing, muscle-relaxation, and imagery predicted greater pre-to-18Mo changes in reactivity and resting RSA, whereas a similar module with less emphasis on slow-breathing did not. Conclusions: Findings raise the possibility that youth reactivity and resting RSA could be modifiable during cognitive behavioral therapy and contribute to the amelioration of psychopathology. More studies are needed to determine whether resting RSA and RSA reactivity are modifiable indices of symptom change in slow-breathing practices and psychotherapy.

CLINICALTRIALS.GOV IDENTIFIER: NCT03153904, registered May 15, 2017.