Monoamine oxidase A gene promoter polymorphism affects novelty seeking and reward dependence in healthy study participantsShiraishi, Hiroaki; Suzuki, Akihito; Fukasawa, Takashi; Aoshima, Toshiaki; Ujiie, Yukihiro; Ishii, Genki; Otani, KoichiPsychiatric Genetics: April 2006 - Volume 16 - Issue 2 - pp 55-58 doi: 10.1097/01.ypg.0000199447.62044.ef Original Articles Abstract Author Information It has been suggested that monoamine oxidase A plays an important role in the characterization of personality. Previous studies on the association between the polymorphism of variable number tandem repeat in the promoter region of the monoamine oxidase A gene and personality traits have, however, been unproductive. In the present study, the association between the monoamine oxidase A variable number tandem repeat polymorphism and personality traits assessed by the Temperament and Character Inventory was examined in 324 Japanese volunteers without psychiatric disorders. The low activity allele with three repeats (allele 3) and high activity allele with four repeats (allele 4) were determined by a polymerase chain reaction method. The carriers of allele 3 in males and the homozygotes of allele 3 in females were classified as the low activity group, the heterozygotes of alleles 3 and 4 in females as the medium activity group, and the carriers of allele 4 in males and the homozygotes of allele 4 in females as the high activity group. One-way analysis of variance showed that the scores of novelty seeking (P=0.006) and reward dependence (P=0.013) were significantly higher in the high activity group than in the low activity group. Multiple regression analysis demonstrated that the excess in the high activity allele was significantly associated with higher scores of novelty seeking (P=0.004) and reward dependence (P=0.003). The present study thus suggests that the monoamine oxidase A variable number tandem repeat polymorphism affects novelty seeking and reward dependence in healthy study participants. Department of Psychiatry, Yamagata University School of Medicine, Yamagata, Japan Correspondence and requests for reprints to Dr Akihito Suzuki, Department of Psychiatry, Yamagata University School of Medicine, 2-2-2 Iidanishi Yamagata City, Yamagata 990-9585, Japan Tel: +81 23 628 5322; fax: +81 23 628 5325; e-mail: firstname.lastname@example.org Received 20 June 2005; Accepted 13 February 2006 © 2006 Lippincott Williams & Wilkins, Inc.