Naltrexone Restored Brain Connectivity Disrupted by Cannabis Use Disorder in Opioid Users

At baseline, people with opioid use disorder plus co-occurring cannabis use disorder showed distinct brain connectivity alterations compared to those with OUD alone, primarily involving the default mode network. Two weeks after naltrexone administration, these connectivity differences globally diminished in the cannabis group. Similar but more limited restoration occurred in co-occurring alcohol use disorder, while no change occurred in co-occurring cocaine use disorder.

Retrospective secondary analysis of fMRI data from individuals with primary opioid use disorder and co-occurring cannabis, alcohol, or cocaine use disorder. All received long-acting intramuscular naltrexone (Vivitrol) and were imaged before and 2 weeks after treatment.

No medication is currently approved for cannabis use disorder. This study provides neuroimaging evidence that naltrexone, already approved for opioid and alcohol use disorders, may address the brain connectivity disruptions specific to cannabis use disorder, potentially offering a treatment pathway.

The lack of approved medications for cannabis use disorder is a major treatment gap. This secondary analysis suggests naltrexone deserves prospective investigation as a CUD treatment, especially since it is already widely available and well-characterized in clinical practice.

Retrospective secondary analysis not designed to study CUD, small subgroup sizes, cannot separate CUD-specific effects from general opioid recovery effects, no behavioral cannabis use outcomes measured, participants had co-occurring OUD complicating interpretation