The A1 allele of the D2 dopamine receptor gene region, alcohol expectancies and drinking refusal self-efficacy are associated with alcohol dependence severity

Abstract

Psychological risk and genetic risk for alcohol dependence are rarely examined in concert. The current study used path analysis (via structural equation modelling) to explore the relationship between the A 1 allele of the D2 dopamine receptor DRD2 gene region, age of problem drinking onset, alcohol expectancy and drinking refusal self-efficacy towards alcohol consumption and dependence severity. One hundred and forty-three (93 male, 50 female) alcohol dependent inpatients provided an extensive clinical history, including age of onset of problem drinking and quantity and frequency of alcohol consumption. The Drinking Expectancy Profile and the Alcohol Dependence Scale were completed, and 10 milliliters of blood were obtained for genetic analysis. The results showed that the posited model fitted the data set well and support the pattern of direct (allele status to drinking) and indirect (allele status influenced by psychosocial variables) relationships hypothesised for the model. A formal test of mediation showed some support for a psychosocial mediational model. The results are discussed in terms of a possible developmental trajectory that involves both genetic risk that influences brain dopamine activity and reinforcement expectancies that both operate via diminished drinking refusal self-efficacy. The prevention and treatment possibilities that arise from understanding this trajectory are examined.