Intertemporal Decision-Making, Nucleus Accumbens Activation, and Alcohol Use Trajectories in Young Adults With a...

A family history of alcohol use disorder (AUD) is associated with increased personal risk for alcohol misuse and AUD. Family history of AUD is also related to increased impulsivity as measured by delay discounting tasks, representing a potential mechanistic link between family history and alcohol misuse. Delay discounting tasks assess individual differences in preferences for smaller, immediate versus larger, delayed rewards, the former being linked to substance misuse. Decision-making on such tasks is underpinned by multiple neural systems, including those supporting reward valuation, cognitive control, and future-oriented thinking. We hypothesized that family history of AUD would be associated with differences in one or more neural systems related to delay discounting, with differences relating to increases in alcohol misuse in young adulthood.

We tested 163 first-year college students (105 females, ages 18-19) with varying levels of familial risk for AUD on a functional magnetic resonance imaging (fMRI) delay discounting task. Alcohol misuse was self-reported at baseline and in 3-yearly follow-up surveys using the Alcohol Use Disorders Identification Test (AUDIT). Change in alcohol misuse was modeled using a latent growth model, and we examined mediation between family history and alcohol misuse trajectory (AUDIT intercept and slope) through functional activation of brain regions implicated in reward valuation (nucleus accumbens), cognitive control (middle frontal gyrus), and future-oriented thinking (hippocampus).

Family history of AUD was associated with greater nucleus accumbens activation (β = 0.286, SE = 0.117, p = 0.014), which in turn predicted a steeper AUDIT slope (β = 0.513, SE = 0.162, p = 0.002). No other mediators were significant.

Our results demonstrate that nucleus accumbens function may be a key mechanism by which family history increases risk for alcohol misuse and AUD.