Impulsive traits and 5-HT2A receptor promoter polymorphism in alcohol dependents: possible association but no influence of personality disorders.

OBJECTIVE Impulsive behavior in alcoholics puts them at serious risk of severer course of disease and has been related to the serotonergic neurotransmission dysfunction. The aim of this study is to investigate the association between impulsive aggression in alcohol dependents with regard to the G-1438A polymorphism in the promoter region of the 5-HT2A receptor gene. Furthermore, we investigated the statistical interaction between 5-HT2A alleles, antisocial personality disorder (APD) and impulsive aggression in alcohol dependents. Alcohol dependents were investigated because these personality disorders and impulsive behavior are very frequent in alcohol dependence anf of clinical relevance. METHODS One hundred and thirty-five patients of German descent meeting DSM-IV criteria of alcohol dependence were recruited. Blood samples were taken from alcohol dependents to determine 5-HT2A promoter polymorphisms using PCR (polymerase chain reaction) of lymphocyte DNA. Impulsive aggression was assessed using a German version of the Barratt Impulsiveness Scale which was translated and backtranslated. Alcohol dependents were subdivided into low- or high-impulsivity groups using a median split of the Barratt score. APD and borderline personality disorder (BPD) were assessed using the SCID-II interview. RESULTS The low-impulsivity group was slightly older and showed a later age at alcoholism onset than the highly impulsive group. Alcohol dependents with high impulsive traits showed a significant association with 5-HT2A 1438 A alleles. After excluding alcohol dependents with APD or BPD from the analysis, this association remained significant. Furthermore, no association between APD, BPD and 5-HT2A alleles was noted. CONCLUSIONS Inpatient alcohol dependents showed a significant association between 5-HT2A A alleles and impulsive traits, independent of the presence of APD or BPD. No association was noted between personality disorders and the polymorphism. This is the first report about an association of 5-HT2A promoter polymorphism and impulsive behavior in alcohol dependents. This finding may refer only to impulsive traits and may be independent of personality disorders in this sample. These results have to be confirmed in larger samples and in healthy control subjects to determine whether this association is of general validity.