DRD4 polymorphism moderates the effect of alcohol consumption on social bonding.

<p>Development of interpersonal relationships is a fundamental human motivation, and behaviors facilitating social bonding are prized. Some individuals experience enhanced reward from alcohol in social contexts and may be at heightened risk for developing and maintaining problematic drinking. We employed a 3 (group beverage condition) ×2 (genotype) design (N = 422) to test the moderating influence of the dopamine D4 receptor gene (DRD4 VNTR) polymorphism on the effects of alcohol on social bonding. A significant gene x environment interaction showed that carriers of at least one copy of the 7-repeat allele reported higher social bonding in the alcohol, relative to placebo or control conditions, whereas alcohol did not affect ratings of 7-absent allele carriers. Carriers of the 7-repeat allele were especially sensitive to alcohol's effects on social bonding. These data converge with other recent gene-environment interaction findings implicating the DRD4 polymorphism in the development of alcohol use disorders, and results suggest a specific pathway by which social factors may increase risk for problematic drinking among 7-repeat carriers. More generally, our findings highlight the potential utility of employing transdisciplinary methods that integrate genetic methodologies, social psychology, and addiction theory to improve theories of alcohol use and abuse.</p

DRD4 VNTR Allele and Genotype Frequencies.

<p>DRD4 VNTR Allele and Genotype Frequencies.</p

Tests of Fixed Effects: Results of Hierarchical Linear Modeling.

<p>Tests of Fixed Effects: Results of Hierarchical Linear Modeling.</p

PGRS Scores (Mean, SE) by DRD4 Genotype and Beverage Condition.

<p>PGRS Scores (Mean, SE) by DRD4 Genotype and Beverage Condition.</p

Beverage Response Variables.

<p>*<i>p</i> = <.05.</p><p>**<i>p</i> = <.001</p><p>†analyses did not include control participants as they were not asked to provide these data</p><p><i>Note.</i> PGRS =  Perceived Group Reinforcement Scale. BAC = blood alcohol concentration. SIS = subjective intoxication scale (values ranging from 0 to 100).</p

DRD4 Genotype Distribution Across Beverage Conditions.

<p>DRD4 Genotype Distribution Across Beverage Conditions.</p

Alcohol and group formation: a multimodal investigation of the effects of alcohol on emotion and social bonding.

<p>We integrated research on emotion and on small groups to address a fundamental and enduring question facing alcohol researchers: What are the specific mechanisms that underlie the reinforcing effects of drinking? In one of the largest alcohol-administration studies yet conducted, we employed a novel group-formation paradigm to evaluate the socioemotional effects of alcohol. Seven hundred twenty social drinkers (360 male, 360 female) were assembled into groups of 3 unacquainted persons each and given a moderate dose of an alcoholic, placebo, or control beverage, which they consumed over 36 min. These groups' social interactions were video recorded, and the duration and sequence of interaction partners' facial and speech behaviors were systematically coded (e.g., using the facial action coding system). Alcohol consumption enhanced individual- and group-level behaviors associated with positive affect, reduced individual-level behaviors associated with negative affect, and elevated self-reported bonding. Our results indicate that alcohol facilitates bonding during group formation. Assessing nonverbal responses in social contexts offers new directions for evaluating the effects of alcohol.</p