['The D1 dopamine receptor has been involved in a number of brain functions, including motor control, inattentive symptoms and reward and reinforcement mechanisms. Indeed, DRD1 antagonists may reduce cocaine-seeking behavior and the acquisition of cocaine-cue associations. The D1.1/r4532 marker of the DRD1 gene has been associated with a large set of phenotypes including addictive behaviors, but none with alcohol dependence per se.', 'We analyzed a population of 134 patients with alcohol dependence, also assessing more homogeneous (severe) phenotypes, comparing this sample with a healthy control population, assessing two SNPs within the DRD1 gene in order to depict the role of DRD1 polymorphisms and haplotypes.', 'The T allele of the rs686 polymorphism within DRD1 gene was significantly more frequent in patients with alcohol dependence (p = 0.0008), with a larger excess for patients with severe dependence (p = 6 x 10(-6)), and even more for patients with severe complications such as withdrawal seizures (p = 7 x 10(-7)). A specific haplotype rs686*T-rs4532*G within the DRD1 gene was significantly more precisely associated with alcohol dependence in our sample (p = 5 x 10(-6)).'] Is a haplotype of the DRD1 gene associated with alcohol dependence?