In vivo 1H magnetic resonance spectroscopy in young-adult daily marijuana users

• The neurochemical profile of the basal ganglia was examined in young marijuana users.
• Glutamate/glutamine levels were lower in female users versus male users and controls.
• Higher myo-inositol levels were observed in female users as compared to other groups.
• Neurochemical impacts of marijuana may be particularly pronounced in females.

To date, there has been little work describing the neurochemical profile of young, heavy marijuana users. In this study, we examined 27 young-adult marijuana users and 26 healthy controls using single-voxel magnetic resonance spectroscopy on a 3 T scanner. The voxel was placed in the dorsal striatum, and estimated concentrations of glutamate + glutamine, myo-inositol, taurine + glucose, total choline and total N-acetylaspartate were examined between groups. There were no overall group effects, but two metabolites showed group by sex interactions. Lower levels of glutamate + glutamine (scaled to total creatine) were observed in female, but not male, marijuana users compared to controls. Higher levels of myo-inositol were observed in female users compared to female non-users and to males in both groups. Findings are discussed in relation to patterns of corticostriatal connectivity and function, in the context of marijuana abuse.