title: Do alcohol-dependent individuals with DRD2 A1 allele have an increased risk of relapse? A pilot study.
abstract: OBJECTIVE
  The TaqIA polymorphism of the dopamine D2 receptor (DRD2) gene has been extensively studied in relation to alcoholism, and the TaqI A1 allele appears to be over-represented in alcohol-dependent individuals. In a recent study, this allele has also been associated with a highly increased mortality rate in alcohol-dependent individuals. In the present study, we investigated whether the TaqI A1 allele of the DRD2 gene region was associated with a higher relapse rate in alcohol-dependent individuals.
  
  
  METHODS
  Adult women (n = 10) and men (n = 40) with a diagnosis of alcohol-dependence were recruited from two Swedish 12-step treatment units for alcoholism. Subjects were genotyped for the TaqIA polymorphism. On average, 1&frac12; year after the end of the treatment program, subjects were re-interviewed by using the alcohol-related items from the Addiction Severity Index follow-up version.
  
  
  RESULTS
  Thirty-three (66%) subjects self-reported relapse and 17 (34%) abstinence during the follow-up period. Thirty-sex percent (18/50) were carriers of the A1 allele of the DRD2 gene region, and 64% (32/50) were non-carriers. Among the carriers of the A1 allele, 89% (16/18) reported relapse in contrast to 53% (17/32) in the non-carriers (P = 0.01; odds ratio = 7.1).
  
  
  CONCLUSIONS
  The present study is, to our knowledge, the first report of an association between the TaqI A1 allele and a substantially increased relapse rate. It should be emphasized that the number of subjects is relatively small, and this investigation should therefore be considered as a pilot study.
authors: Department of Psychology, University of Gothenburg, PO Box 500, SE-405 30 Göteborg, Sweden.
authors: Angelica
authors: A
authors: Dahlgren
authors: Hanna-Linn
authors: HL
authors: Wargelius
authors: Kristina J
authors: KJ
authors: Berglund
authors: Claudia
authors: C
authors: Fahlke
authors: Kaj
authors: K
authors: Blennow
authors: Henrik
authors: H
authors: Zetterberg
authors: Lars
authors: L
authors: Oreland
authors: Ulf
authors: U
authors: Berggren
authors: Jan
authors: J
authors: Balldin