D-2 AND D-4 DOPAMINE-RECEPTOR POLYMORPHISMS AND PERSONALITY

The relationship of various dimensions of temperament, measured by the Tridimensional Personality Questionnaire (TPQ), to polymorphisms of t he D-2 dopamine receptor (DRD2) and D-4 dopamine receptor (DRD4) genes was determined in 119 healthy Caucasian boys who had not yet begun to consume alcohol and other drugs of abuse. Total Novelty Seeking score of the TPQ was significantly higher in boys having, in common, all th ree minor (A1,B1, and Intron 6 1) alleles of the DRD2 compared to boys without any of these alleles, Boys with the DRD4 7 repeat (7R) allele also had a significantly higher Novelty Seeking score than those with out this allele, However, the greatest difference in Novelty Seeking s core was found when boys having all three minor DRD2 alleles and the D RD4 7R allele were contrasted to those without any of these alleles, N either the DRD2 nor the DRD4 polymorphisms differentiated total Harm A voidance score, Whereas subjects having all three minor DRD2 alleles h ad a significantly higher Reward Dependence 2 (Persistence) score than subjects without any of these alleles, no significant difference in t his personality score was found between subjects with and without the DRD4 7R allele, In conclusion, DRD2 and DRD4 polymorphisms individuall y associate with Novelty Seeking behavior. However, the combined DRD2 and DRD4 polymorphisms contribute more markedly to this behavior than when these two gene polymorphisms are individually considered. (C) 199 8 Wiley-Liss, Inc.