title: Cannabinoid receptor 1 gene association with nicotine dependence.
abstract: BACKGROUND
  The endogenous cannabinoid system has been implicated in drug addiction in animal models. The cannabinoid receptor 1 (CNR1) gene is 1 of the 2 receptors expressed in the brain. It has been reported to be associated with alcoholism and multiple drug abuse and dependence.
  
  
  OBJECTIVE
  To test the hypothesis that the CNR1 gene is associated with nicotine dependence.
  
  
  METHODS
  Genotype-phenotype association study. Ten single-nucleotide polymorphisms were genotyped in the CNR1 gene in 2 independent samples. For the first sample (n = 688), a 3-group case-control design was used to test allele association with smoking initiation and nicotine dependence. For the second sample (n = 961), association was assessed with scores from the Fagerström Test for Nicotine Dependence (FTND). Settings Population samples selected from the Mid-Atlantic Twin Registry.
  
  
  METHODS
  White patients aged 18 to 65 years who met the criteria of inclusion.
  
  
  METHODS
  Fagerström Tolerance Questionnaire and FTND scores.
  
  
  RESULTS
  Significant single-marker and haplotype associations were found in both samples, and the associations were female specific. Haplotype 1-1-2 of markers rs2023239-rs12720071-rs806368 was associated with nicotine dependence and FTND score in the 2 samples (P < .001 and P = .009, respectively).
  
  
  CONCLUSIONS
  Variants and haplotypes in the CNR1 gene may alter the risk for nicotine dependence, and the associations are likely sex specific.
authors.affiliation: Virginia Institute for Psychiatric and Behavioral Genetics and Department of Psychiatry, Virginia Commonwealth University, 800 Leigh St, Ste 1-110, Richmond, VA 23298, USA. xchen@vcu.edu
authors.forename: Xiangning
authors.initials: X
authors.lastname: Chen
authors.forename: Vernell S
authors.initials: VS
authors.lastname: Williamson
authors.forename: Seon-Sook
authors.initials: SS
authors.lastname: An
authors.forename: John M
authors.initials: JM
authors.lastname: Hettema
authors.forename: Steven H
authors.initials: SH
authors.lastname: Aggen
authors.forename: Michael C
authors.initials: MC
authors.lastname: Neale
authors.forename: Kenneth S
authors.initials: KS
authors.lastname: Kendler
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D015870:Gene Expression / Q000235:genetics*; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D043884:Receptor, Cannabinoid, CB1 / Q000235:genetics*; D014029:Tobacco Use Disorder / Q000235:genetics*; D014427:Twins / Q000235:genetics
chemical_list: D043884:Receptor, Cannabinoid, CB1