5-HTTLPR genotype and associations with intoxication and intention to drive: Results from a field study of bar patrons

The serotonin transporter promoter polymorphism (5-HTTLPR) has been linked to a number of human behavioral traits and disorders. The variants of 5-HTTLPR are commonly reported in three forms, L/L, S/L and S/S, with the latter most often associated with emotional distress and/or behavioral dysfunction. Missing from the research literature are investigations that assess event-level associations between 5-HTTLPR genotype and specific incidents of risk behavior in natural drinking settings. This study reports associations between 5-HTTLPR, alcohol intoxication and intention to drive among young adult patrons exiting on-premise drinking establishments (i.e. bars) at night. Self-report measures, breath alcohol concentration (BrAC) readings and saliva samples for DNA analysis were collected from 477 bar patrons. Analyses were performed on 225 patrons likely to be near their peak intoxication level for the night. Results from a linear regression revealed that the 5-HTTLPR genotype was associated with exiting patron BrAC, after adjusting for random and fixed effects of other variables. An interaction effect involving 5-HTTLPR and bar-sponsored drink specials also had an independent association with BrAC, suggesting that selection of price-discounted alcoholic beverages increased intoxication in patrons with an L allele. In addition, results from logistic regression indicated that patrons with the S/S genotype were three times more likely to intend to drive a motor vehicle (after drinking on the night of study participation) compared with those with the L/L genotype. The 5-HTTLPR genotype may play an important role in the etiology of problems associated with on-premise drinking establishments.