The genotypes of three DNA sequence variants in exons 1a1, 7 and 11 of the GABABR1 gene were assessed in 234 German controls and 350 German alcohol-dependent subjects, including three more homogeneous subgroups of alcoholics, marked by (1) history of parental alcoholism (n = 121); (2) history of alcohol withdrawal seizure or delirium (n = 108); and (3) comorbidity of dissocial personality disorder (n = 60).