A Preliminary Prospective Study of an Escalation in 'Maximum Daily Drinks', Fronto-Parietal Circuitry and Impulsivity-Related Domains in Young Adult Drinkers.

Excessive alcohol use in young adults is associated with greater impulsivity and neurobiological alterations in executive control systems. The maximum number of drinks consumed during drinking occasions ('MaxDrinks') represents a phenotype linked to vulnerability of alcohol use disorders, and an increase, or 'escalation', in MaxDrinks may be indicative of greater risk for problematic drinking. Thirty-six young adult drinkers performed a Go/No-Go task during fMRI, completed impulsivity-related assessments, and provided monthly reports of alcohol use during a 12-month follow-up period. Participants were characterized by MaxDrinks at baseline and after follow-up, identifying 18 escalating drinkers and 18 constant drinkers. Independent component analysis was used to investigate functional brain networks associated with response inhibition, and relationships with principal component analysis derived impulsivity-related domains were examined. Greater baseline MaxDrinks was associated with an average reduction in the engagement of a right-lateralized fronto-parietal functional network, while an escalation in MaxDrinks was associated with a greater difference in fronto-parietal engagement between successful inhibitions and error trials. Escalating drinkers displayed greater impulsivity/compulsivity-related domain scores that were positively associated with fronto-parietal network engagement and change in MaxDrinks during follow-up. In young adults, an escalating MaxDrinks trajectory was prospectively associated with altered fronto-parietal control mechanisms and greater impulsivity/compulsivity scores. Continued longitudinal studies of MaxDrinks trajectories, functional network activity, and impulsivity/compulsivity-related features may lend further insight into an intermediate phenotype vulnerable for alcohol use and addictive disorders.