Heart Rate Variability Mediates the Relationship between Dispositional Mindfulness and Opioid Craving Among Chronic Pain Patients

Background and Purpose: Chronic pain conditions affect nearly one third of the US population. They are more prevalent than diabetes, heart disease, and cancer, combined, and cost the country an estimated $635 billion annually in missed work, lost productivity and medical bills. Opioid analgesic medications are often the frontline treatment for chronic pain, however these medications often provide inadequate relief, and extended treatment with these medications contributes to a rising public health epidemic of opioid addiction. Opioid addiction is marked by craving for opioids irrespective of the need to obtain pain relief, a craving that is manifested by physiological reactivity to opioid-related cues coupled with a subjective wanting for the drug. Mindfulness may be an effective means of countering this addictive tendency. In that regard, mindfulness been associated with increased self-regulation of responses to drug-related stimuli. Such self-regulatory efficacy may be indexed by high frequency heart rate variability (HRV), a measure of adaptive autonomic control. Hence, this study examined the effect of dispositional mindfulness on opioid craving and heart rate variability (HRV) responses while viewing opioid cues. We hypothesized that the inverse association between mindfulness and craving would be partially mediated by enhanced HRV during opioid cue-exposure. 

Methods: This cross-sectional, secondary analysis examined data obtained from a sample of chronic pain patients (N=115) who participated in a randomized controlled trial (Garland et al., 2014). Participants completed self-report measures of mindfulness (Five Facet Mindfulness Questionnaire) and opioid craving (Obsessive Compulsive Drug Use Scale), and HRV was measured during an opioid-cue dot probe task. Pearson bivariate correlations between dispositional mindfulness, HRV and opioid craving were then computed, and a path analysis was used to examine HRV has a mediator in the relationship between dispositional mindfulness and opioid craving.

Results: Path analysis revealed that baseline dispositional mindfulness was significantly positively correlated with HRV (B = .544, SE = 0.20, p = .007), and HRV was significantly inversely associated with opioid craving (B = -0.071, SE = 0.26, p = .006). A significant indirect effect of mindfulness on opioid craving through HRV was also observed (B = -1.99, SE = .019, p = .04). Results provide evidence that dispositional mindfulness may buffer against opioid craving among chronic pain patients prescribed long-term opioid therapy, and that this buffering effect may be a function of improved parasympathetic activation.

Conclusions and Implications: Mindfulness appears to protect against opioid craving by virtue of improving self-regulation of physiological reactions to opioid cues. Accordingly, social workers may benefit from knowledge of and training in mindfulness-based interventions in order to better serve populations at risk for the development of opioid misuse disorders.