A multimethod examination of impulsivity and its association with gamma-aminobutyric acid (GABA), glutamate, and other neurometabolite levels in youth who do and do not use alcohol.

BACKGROUND

Minimal research has examined neurochemical alterations underlying the relationship between impulsivity and alcohol use in youth. We examined associations between multimethod impulsivity measures and neurometabolite levels in youth who use alcohol compared to controls.

METHODS

Using baseline data from two clinical trials with youth (age 16-22) who used alcohol (N = 82, 65 % female) and healthy controls (N = 22, 50 % female), we measured levels of glutamate-related metabolites (glutamate [Glu] and glutamate + glutamine [Glx]) and GABA, and other exploratory neurometabolites (glutathione, total N-acetylaspartate [tNAA], total choline-containing metabolites [tCho], and myo-inositol), in the dorsal anterior cingulate cortex using proton magnetic resonance spectroscopy. Trait impulsivity was measured via the Barratt Impulsiveness Scale (BIS-11), and behavioral impulsivity was measured via the D-KEFS Color-Word Interference Test and the Cash Choice Task.

RESULTS

Compared to controls, youth who use alcohol had higher impulsivity on the BIS-11 attentional, non-planning, and motor subscales. There were no significant interactions between group (alcohol, control) and impulsivity variables in predicting Glu, Glx, or GABA levels. In exploratory analyses, better inhibitory control and lower non-planning impulsivity in youth who use alcohol was associated with higher glutathione levels; however, the opposite relationship was found for controls.

CONCLUSIONS

These preliminary findings suggest trait, but not behavioral, impulsivity is significantly associated with alcohol use in youth. Glutathione may have differential associations with distinct impulsivity constructs in youth who use alcohol compared to controls. Further research is needed to corroborate these associations and their implications for understanding the neurochemical basis of impulsivity and alcohol use in youth.