Heart rate variability and heart rate in a sample of medicated and unmedicated adolescents with obsessive-compulsive disorder.

OBJECTIVE: Alterations in autonomic nervous system activity - measured by heart rate variability (HRV) and heart rate (HR) - have been proposed as a relevant biopsychological mechanism in several psychiatric disorders. However, only few studies have examined these parameters in OCD, and evidence from pediatric samples is particularly limited. The aim of this study was to investigate autonomic activity in pediatric OCD. METHODS: A five minute resting state electrocardiogram was recorded in adolescents with OCD (n = 64) and age- and IQ-matched healthy controls (HC, n = 52). Autonomic activity was compared using the logarithmized root mean square of differences between successive R-R intervals (logRMSSD), the logarithmized high-frequency HRV (logHF-HRV), the percentage of adjacent NN intervals differing from each other by more than 50 ms (pNN50) and HR. Associations with psychotropic medication status and symptom severity were assessed. RESULTS: Adolescents with OCD showed lower logRMSSD and higher HR than HC, whereas logHF-HRV and pNN50 did not differ between groups. No associations were found between cardiac measures and OCD symptom severity. Exploratory subgroup analyses suggested lower logHF-HRV and logRMSSD in medicated adolescents with OCD. CONCLUSIONS: Our findings add to evidence for altered autonomic activity in pediatric OCD, reflected by elevated HR and lower RMSSD. The observed reduction in HRV did not increase with greater symptom severity and appeared most pronounced among medicated adolescents with OCD. SIGNIFICANCE: The autonomic imbalance observable in adolescents with OCD is common across anxiety disorders and has been linked to cardiovascular risk.