A preliminary investigation of the acute effects of delta-9-tetrahydrocannabinol on pain and opioid attentional bias among persons with opioid use disorder.

INTRODUCTION: Attentional bias (AB) is believed to be an important factor in the development and maintenance of both opioid use disorder (OUD) and chronic pain. Cannabis and its main psychoactive constituent, delta-9-tetrahydrocannabinol (THC), produce analgesic effects via processes that are potentially relevant to AB and is commonly used by persons with OUD. This exploratory study investigated if THC influences AB towards pain and opioid cues individuals with OUD.

METHODS: Using a within-subject, crossover design, 27 adults receiving methadone were randomly assigned to receive single doses of oral THC (10 mg, 20 mg administered as dronabinol) or placebo across three, 5-h sessions. During each session, a visual probe task was used to measure AB to pain and opioid cues at baseline and 120 min post-THC administration.

RESULTS: Mixed-effects models examined main effects of THC dose, time, and their interaction across all participants; findings were then stratified by methadone dose (low dose <90 mg/day and high dose ≥90 mg/day). Among individuals receiving high doses of methadone, a significant interaction was observed such that AB towards opioids increased following 10 mg THC administration and decreased following 20 mg THC administration. Additionally, participants receiving low doses of methadone showed significant increases in the variability of opioid-related AB post THC administration.

CONCLUSION: We provide preliminary evidence showing that THC may cause dose-dependent effects on selective attention for opioid cues among methadone patients. These results underscore the need for further clinical investigation into the effects of cannabinoids and other substances with potential analgesic and addictive properties among persons with OUD.