LACK OF ASSOCIATION BETWEEN THE DOPAMINE D2 RECEPTOR GENE ALLELE DRD2-ASTERISK-A1 AND CIGARETTE-SMOKING IN A UNITED-KINGDOM POPULATION

The dopamine D2 receptor gene contains a TaqI repeat fragment length p olymorphism creating two alleles DRD2A1 and DRD2*A2, It has been prev iously suggested that the lesser allele, DRD2A1, is more prevalent in individuals who are susceptible to impulsive/addictive/compulsive beh aviour, for example, alcoholics, polysubstance abusers and tobacco smo kers, We genotyped a series of 104 smokers and 117 non smokers and com pared the allele frequencies between the groups, A subset (n = 87) of the smoking population also completed the Classification of Smoking by Motives questionnaire and were given scores for five criteria that dr ive smoking: automatic, dependence, sedative, stimulant and indulgence , Another subset (n = 52) completed the Fagerstrom Tolerance Questionn aire and were given scores for nicotine dependence, We did not find an y increase in allele A1 frequency when comparing smokers to non smoker s. Furthermore, neither measure of dependence was affected by possessi on of the A1 allele; the only difference between DRD2A1 bearing and D RD2A2 homozygous individuals in terms of smoking motives was found in the scores for indulgence; the former having a moderately reduced sco re (by 17%, p < 0.05). We conclude that, in the individuals studied, t he dopamine D2 receptor TaqI locus does not affect the drive to smoke, This may be caused by the locus being unrelated to impulsive/addictiv e/compulsive behaviour, the polymorphism being in linkage disequilibri um with another distinct locus or, alternatively, smoking may represen t a behaviour that is not directly comparable to impulsive/addictive/c ompulsive behaviours previously associated with the DRD2A1 allele. Ph armacogenetics 8: 125-128 (C) 1998 Lippincott-Raven Publishers.