Heart Rate Variability in Adults With Substance Use Disorder: A Comprehensive Narrative Review.

Background: Heart rate variability (HRV) is an indicator of autonomic abnormalities. However, little is known about the role of HRV related to substance use behavior and the association between the changes in HRV and signs of relapse in substance use. Aim: The purpose of this study was to review the existing literature on autonomic response to substance use (i.e., opioids, cocaine, and methamphetamine) measured by HRV and its outcomes related to the risk factors of relapse. Methods: A systematic search of the literature was conducted using PubMed, PsychINFO, and Ovid Medline databases. The study includes full-text articles published in English from 2010 to 2020, using measures of HRV in human subjects who use substances. Results: A total of 14 studies were reviewed. Studies included outpatients with a prescription or nonprescription opioid misuse behavior with a primary diagnosis being chronic pain or substance use disorder (SUD). Significantly decreased resting HRV was found in substance users compared to healthy controls. Lower resting HRV has been significantly associated with stress, craving, and greater symptom severities in individuals with SUD and other substance dependence. HRV indices can be potential measures of homeostatic imbalance and self-regulation flexibility. Conclusion: HRV may be a useful tool for monitoring early indication of relapse so that relapse prevention measures can be implemented in a timely manner. Future studies in substance use may benefit from examining HRV in relations to substance use and relapse signs and symptoms in a larger population to guide future relapse prevention strategies. [ABSTRACT FROM AUTHOR]