P300 in alcohol dependence: Effects of TaqI-A genotype

Background and Objectives: TaqI-A polymorphism, related to D2 dopamine receptor (DRD2), and event-related P300 potentials have been considered markers of alcohol dependence. The effect of alcohol use variables and TaqI-A on P300 in a single sample have been hardly analysed previously. This study examined changes in P300 parameters after six months of abstinence in alcohol-dependent subjects classified by their TaqI-A genotype. Methods, 102 men with alcohol dependence were studied at baseline and at 6 months of continued abstinence. P300 was recorded using an auditory paradigm. TaqI-A polymorphism was genotyped: 34.3% of sample was classified as A1[TaqI-A1/TaqI-A1and TaqI-A1/TaqI-A2] and 65.7% as A2 [TaqI-A2/TaqI-A2]. The association between P300 and TaqI-A and the correlation with age and alcohol consumption were considered. Results: The abstinence period was not associated to differences in neither P300 latency (F[l, 99] = 1.154 p = 0.285) nor amplitude (F[l, 99] = 1.453, p = 0.231). A1 subgroup was related to a longer latency (F[l, 99] = 5.055 p = 0.027), an early abuse age onset (F[l, 100] = 14.552 p < 0.001) and close to be significant to an early dependence age onset (F[l, 100] = 3.868 p = 0.052). Other drinking pattern variables were not associated to p300 measures. Family history for alcoholism and TaqI-A were not related (X[l] = 0.327 p = 0.568) and no association was found with p300 measures. Current age correlated positively with P300 latency (F[l, 99] = 26.082, p < 0,001) and negatively with amplitude (F[l, 99] = 5.297 p = 0.023). P300 amplitude was not influenced by alcohol use variables nor TaqI-A polymorphism. Conclusions: P300 latency could be a biological marker of vulnerability to alcohol dependence related to TaqI-A1 polymorphism, irrespective of alcohol use variables. Adapted from the source document.