Resting Heart Rate Variability: Exploring Associations With Symptom Severity in Adults With Substance Use Disorders...

Objective: Substance use disorders and posttraumatic stress symptoms are commonly comorbid. Previous studies have established that those with substance use disorders or posttraumatic stress disorder (PTSD) have lower high frequency-heart rate variability (HF-HRV) compared to controls, suggesting that low HF-HRV may be a biomarker of a common physiological mechanism underlying both disorders. We evaluated HF-HRV as a potential biomarker of a common underlying process by testing whether lower HF-HRV related to greater severity of substance use and PTSD symptoms in individuals with both substance use disorders and at least four symptoms of PTSD. Methods: HF-HRV was measured in 49 adults with substance use disorders and at least four symptoms of PTSD. We performed a series of regressions controlling for age to test whether low HF-HRV was associated with greater substance use disorder and PTSD symptom severity. Substance use disorder symptoms were measured by the Addiction Severity Index and PTSD symptoms were measured by the Clinician-Administered PTSD Scale and the PTSD Checklist. Results: After controlling for age, low resting HF-HRV was significantly associated with drug and alcohol symptom severity but not PTSD symptom severity. Conclusions: HF-HRV may be more sensitive to the severity of drug and alcohol use rather than PTSD. Findings may suggest that in PTSD populations, HF-HRV may primarily index comorbid substance use disorder symptoms. HF-HRV could serve as an objective measure of substance use severity and should be further investigated as a predictor of outcomes in treatment for substance use disorders.