The heart rate dynamics and antioxidant capacity under cognitive load in Obsessive-Compulsive disorder

The research of the oxidants-antioxidants homeostasis and its connection to autonomic nervous system (ANS) dysfunction in patients with obsessive-compulsive disorder (OCD) is a relatively uncharted field of study. We recruited 31 patients diagnosed with OCD and 29 healthy volunteers to analyze their saliva antioxidant capacity before and after a three-block behavioral task with cognitive and emotional load, during which we assessed heart rate (HR) and heart rate variability (HRV) patterns. We found that the OCD group had a significantly lower antioxidant capacity (AOC) and showed no increase in AOC after the cognitive task as compared with healthy volunteers. The notable negative correlation between HR and AOC changes led us to select two subgroups inside the OCD and control group: one with high HR and another with low HR. The AOC changes for OCD and healthy participants with high HR were similar, while OCD sub-group with low HR exhibited significantly different changes in AOC compared with the control group. Although HRV did not show a correlation with AOC, the OCD group demonstrated substantially higher increase of very low frequencies (VLF) of HRV during the cognitive task performance and significantly elevated low frequency powers of HRV expressed in normal units (LFnu). OCD sub-group with lower HR exhibited higher LFnu compared to both the patient and the control group with high HR. Our findings imply that OCD patients with elevated sympathetic tone of ANS reflected by initially increased HR show more adaptive AOC to cognitive load