Evaluating the Feasibility, Acceptability, and Preliminary Outcomes of Heart Rate Variability Biofeedback for Individuals With Opioid Use Disorder.

The goal of this clinical trial is to evaluate the feasibility, acceptability, and preliminary outcomes of a heart rate variability biofeedback (HRVB) intervention among adults with opioid use disorder (OUD) receiving residential treatment. The study aims to learn whether HRVB can be implemented successfully in this setting and whether it may help participants manage stress, emotional regulation, and cravings. The main questions this study aims to answer are: Is HRVB feasible and acceptable for adults with OUD in a residential treatment program, as indicated by recruitment, retention, adherence, and participant satisfaction? Do participants show preliminary improvements in stress, affect, emotional regulation, self-efficacy, and cravings following participation in the HRVB intervention? Participants will be adults with OUD enrolled in a residential treatment program. Participants will: 1. Complete baseline and post-intervention questionnaires assessing stress, affect, emotional regulation, social support, self-efficacy, and cravings 2. Participate in daily HRVB practice using a portable biofeedback device for approximately 3 weeks 3. Complete brief daily diary assessments related to mood, stress, and cravings This is a single-arm pilot study designed to inform the feasibility and future refinement of HRVB as an adjunct intervention for individuals with OUD in residential treatment settings.