Reward Sensitivity in Patients Receiving Opioid Agonist and Antagonist Treatment for Opioid Use Disorder: An Observational Study

Background. Disrupted reward processing is a core component in neurobiological theories of addictions, including opioid use disorder (OUD). While acute opioid agonist and antagonist administration can modulate reward behavior and experiences, it remains unclear how typical long-term OUD treatment with these medications impact patients’ sensitivity to substance-free rewards. We therefore conducted a cross-sectional study of reward sensitivity in opioid agonist- and antagonist-treated OUD patients, and healthy volunteers.Methods. Ninety-six OUD patients on extended-release naltrexone (n=45) or opioid agonists (n=51) and 50 healthy volunteers completed a probabilistic reward task (PRT) and self-report measures of anhedonia, depression, preoccupation with immediate consequences, substance craving and life satisfaction in a single session. We used signal detection analysis and drift diffusion modeling to derive behavioral reward bias measures from PRT performance. Group differences were modeled with beta and linear regression.Results. Patients reported significantly greater anhedonia (Cohen’s ds≥0.64), depression (ds≥0.53) and preoccupation with immediate consequences (ds≥0.54) than heathy volunteers, but differences between naltrexone- and opioid agonist-treated patients were non-significant (ds≤0.26). Group differences in behavioral reward bias were small and non-significant (ps=1, BF01s≥84.13). Anhedonia was significantly associated with lower life satisfaction (OR [95% CI]=1.10 [1.04, 1.17]). There were no other significant associations between reward sensitivity measures and life satisfaction or craving (ps≥0.31, BF01s≥2.58).Conclusion. These data support an association between OUD and reduced well-being irrespective of opioid agonist or antagonist treatment, highlighting patients’ need for psychosocial support and/or adjunct interventions. Major detrimental effects of naltrexone treatment on well-being seem unlikely from these and previous results.