A study published in Drug and Alcohol Dependence suggests that co-using alcohol and cannabis does not produce additional changes in brain connectivity compared to heavy alcohol use alone.
(Photo credit: RespectMyRegion.com).
For the study, researchers from the University of California conducted a secondary analysis of three clinical laboratory studies, examining resting-state functional connectivity (rsFC) in 60 individuals.
Participants were categorized into three groups: controls with no regular drug use (16), heavy alcohol users (27), and individuals who regularly used both alcohol and cannabis (17). Resting-state fMRI scans were analyzed to assess connectivity differences in the salience network, a brain system associated with attention and addiction.
The findings revealed significant differences in rsFC between the anterior cingulate cortex, anterior insula, and supramarginal gyrus—regions linked to motor, sensory, visual, and executive control functioning. Both the alcohol-only and alcohol-cannabis co-use groups exhibited reduced rsFC compared to controls (p<0.05), but there were no significant differences between the alcohol-only and co-use groups.
These results suggest that cannabis does not exert an additional or opposing effect on rsFC in individuals who co-use alcohol and cannabis. Instead, alcohol may be the primary driver of neural alterations linked to inhibitory control and substance craving.
“This preliminary study suggests that co-using alcohol-cannabis may not be associated with any additive or contrasting effects on rsFC compared to using alcohol alone”, concludes the study. “Thus, in individuals who co-use alcohol-cannabis, alcohol may drive neural alterations associated with inhibitory control and substance craving.”
