Cannabis use moderates the relationship between pain and negative affect in adults with opioid use disorder

Introduction Adults in Medication-Assisted Treatment (MAT) for opioid addiction are at risk for substance use relapse and opioid overdose. They often have high rates of cannabis use and comorbid symptoms of pain, depression, and anxiety. Low levels of self-efficacy (confidence that one can self-manage symptoms) are linked to higher symptom burdens and increased substance use. The effects of cannabis use on symptom management among adults with MAT are currently unclear. Therefore, the primary purpose of this study is to examine whether cannabis use moderates the relationships between pain and negative affect (i.e., depression and anxiety) and whether self-efficacy influences these interactions. Methods: A total of 150 adults receiving MAT and attending one of two opioid treatment program clinics were administered a survey containing measures of pain, depression, anxiety, self-efficacy, and cannabis use. Results: Cannabis use frequency moderated the relationships between pain and depression as well as pain and anxiety. Specifically, as cannabis use frequency increased, the positive relationships between pain and depression and pain and anxiety grew stronger. However, cannabis use was no longer a significant moderator after controlling for self-efficacy. Conclusions: Results suggest that cannabis use strengthens, rather than weakens, the relationships between pain and depression and pain and anxiety. These effects appear to be driven by decreased self-efficacy in cannabis users. It is important to understand how self-efficacy can be improved through symptom self-management interventions and whether self-efficacy can improve distressing symptoms for people in MAT.