Clinical and psychosocial changes in adults with opioid use disorder and chronic pain using medical cannabis: a brief report.

Background: Medical cannabis (MC) is approved for the treatment of opioid use disorder (OUD) in Pennsylvania, but little is known about how MC impacts illicit opioid use or the clinical and psychosocial factors including pain severity levels that can precede illicit opioid use. This observational study examined the extent to which changes in rates of illicit opioid use and in pain and psychosocial functioning were observed following the first three months of MC treatment.

Methods: A referred sample of 47 adults taking buprenorphine/naloxone for OUD with a minimum pain severity rating of 5/10 enrolled from March 2022-April 2023. Participants were recruited from an outpatient MC physician recommender's office and were offered a discounted MC 1:1 tetrahydrocannabinol:cannabidiol 5 mg:5 mg daily oral capsule. The primary study outcomes were pain severity, self-efficacy and interference, and the rates of illicit substance use as assessed via urine drug screening (UDS).

Results: Participants (64% male, 49% Black, average age = 44 years) reported significant decreases in pain severity from baseline (M = 5.18, SD = 2.09) to Month 3 (M = 4.39, SD = 2.28), P < 0.01, Cohen's d = 0.54, and pain interference from baseline (M = 5.21, SD = 2.79) to Month 3 (M = 4.32, SD = 2.86), P < 0.01, Cohen's d = 0.47, and increases in pain-related self-efficacy from baseline (M = 6.55, SD = 3.57) to Month 3 (M = 8.05, SD = 3.30), P < 0.01, Cohen's d = 0.44. Rates of opioid use (X²[1] = 4.00, P = 0.13) did not differ significantly from baseline (16%) to Month 3 (5%). Cravings for opioids were mildly higher at baseline (M = 2.15, SD = 2.88) than at 3-months (M = 1.78, SD = 2.95) but this difference was not statistically significant, P = 0.49, d = 0.1. Sleep quality scores improved significantly from baseline (M = 12.38, SD = 4.40) to Month 3 (M = 10.95, SD = 4.95), P < 0.05, d = 0.33. Quality of life significantly improved in seven of eight domains (P < 0.05).

Conclusion: MC treatment initiation was associated with reductions in pain severity and interference and improvements in quality of life and sleep quality, but not in illicit opioid use or cravings in adults with chronic pain receiving buprenorphine/naloxone for OUD.