A psychometrically derived impulsive trait related to a polymorphism in the serotonin transporter gene-linked polymorphic region (5-HTTLPR) in a Japanese nonclinical population: assessment by the Barratt impulsiveness scale (BIS)

Although a number of studies have shown that human impulsive traits are associated with indices of central serotonin function, few researchers have investigated the relationship between a polymorphism in the serotonin transporter gene-linked region (5-HTTLPR) and a psychometrically derived impulsive trait. We determined the 5-HTTLPR polymorphism in 123 employed Japanese male adults using the polymerase chain reaction. The distribution of allelic frequency was determined and also investigated the relationship of the 5-HTTLPR polymorphism to a impulsive trait as measured by the Barratt Impulsiveness Scale, 11th version (BIS-11). The distribution of allelic frequency was found to be almost identical to that previously reported in Japanese (the frequency for the long (L)/L, L/short (S), and S/S genotypes was: 3, 28, and 68%, respectively). In a comparison between the genotype groups, the S/S genotype group significantly higher scored for the total BIS-11 and the subscale attentional impulsiveness than the L/S + L/L genotype group. These findings suggest that individuals with a homozygous S-allele may be more impulsive than those with the other genotype.