AUTHOR=Smith Christopher T. , Steel Eleanor A. , Parrish Michael H. , Kelm Mary K. , Boettiger Charlotte A. 

TITLE=Intertemporal Choice Behavior in Emerging Adults and Adults: Effects of Age Interact with Alcohol Use and Family History Status

JOURNAL=Frontiers in Human Neuroscience

VOLUME=9

YEAR=2015

URL=https://www.frontiersin.org/journals/human-neuroscience/articles/10.3389/fnhum.2015.00627

DOI=10.3389/fnhum.2015.00627

ISSN=1662-5161

ABSTRACT=<p>Adults with alcohol use disorders (AUDs) show marked immediate reward selection (or “<italic>Now</italic>”) bias in intertemporal choice tasks. This <italic>Now</italic> bias persists long into abstinence, suggesting an irreversible consequence of chronic alcohol abuse or a pre-existing AUD intermediate phenotype. However, some data show substantial <italic>Now</italic> bias among emerging adults (18–25), regardless of drinking behavior, suggesting age-dependent effects on <italic>Now</italic> bias. The objectives of the present study were to determine (1) whether <italic>Now</italic> bias is greater among emerging adults relative to adults, (2) whether any such age effect on <italic>Now</italic> bias is diminished in sub-clinical heavy alcohol users, and (3) whether having a problem drinking first degree relative is independently associated with elevated <italic>Now</italic> bias. To achieve these objectives, we used an intertemporal choice task to quantify <italic>Now</italic> bias in <italic>n</italic> = 237 healthy participants (ages 18–40; 50% female), and a wide range of non-zero alcohol use, based on the Alcohol Use Disorders Identification Test (AUDIT). We found that among non-heavy drinkers, <italic>Now</italic> bias inversely correlated with age; this relationship was not present among heavy drinkers. We found no significant relationship between AUDIT score and <italic>Now</italic> bias among emerging adults, but AUDIT scores and <italic>Now</italic> bias were positively correlated among 26–40 year olds. Additionally, non-heavy drinking adults who reported a problem drinking first degree relative showed greater <italic>Now</italic> bias compared to those not reporting familial problem drinking. While not definitive, these findings lend support for elevated <italic>Now</italic> bias in adulthood as an intermediate phenotype for AUDs. Moreover, non-additive effects of age and heavy drinking on <italic>Now</italic> bias suggest perturbations in largely common neural circuits in both groups.</p>