A preliminary study: novelty seeking, frontal executive function, and dopamine receptor (D2) TaqI A gene polymorphism in patients with methamphetamine dependence.
BACKGROUND
Dopamine receptor polymorphisms have been associated with specific patterns of novelty seeking (NS) temperamental nature and frontal executive function. In addition, carriers of dopamine receptor type 2 (DRD2)-TaqI A1 have been hypothesized to be potentially vulnerable to addictive behaviors. In the present study, the association between dopamine D2 polymorphisms, NS, and frontal executive function was studied.


METHODS
Thirty-seven methamphetamine (MA)-dependent subjects and 40 healthy comparison subjects participated in the current study. The severity of addiction, NS temperament, and frontal executive functions were measured using the Addiction Severity Index, the NS subscale in the Temperament and Character Inventory, and the Wisconsin Card Sorting Test, respectively. All subjects were genotyped with regard to DRD2-TaqI polymorphisms.


RESULTS
The prevalence of DRD2-TaqI A1 allele polymorphisms was greater in the MA-abuser group than in the comparison group. Patients with MA dependence also had higher NS characteristics and high scores in total trials, errors, and perseverative errors of the Wisconsin Card Sorting Test than comparison subjects. Within patients with MA dependence, the subgroup of DRD2-TaqI A1 carrier had greater NS scores relative to those without, whereas there was only a trend level of lower frontal executive function in the first subgroup.


CONCLUSIONS
In the present study, the MA-dependent patients with DRD2-TaqI A1 allele had significantly greater NS scores and lower frontal executive function with a trend level than those without. These preliminary results suggest that MA-dependent patients may have the possibility of genetic and biogenic vulnerability to MA.
McLean Hospital Brain Imaging Center and Department of Psychiatry, Harvard Medical School, Belmont, MA 02478, USA.
Doug Hyun
DH
Han
Sujung J
SJ
Yoon
Young Hoon
YH
Sung
Young Sik
YS
Lee
Baik Seok
BS
Kee
In Kyoon
IK
Lyoo
Perry F
PF
Renshaw
Soo Churl
SC
Cho
D000328:Adult; D000483:Alleles; D019969:Amphetamine-Related Disorders / Q000453:epidemiology / Q000235:genetics* / Q000503:physiopathology; D001288:Attention / Q000502:physiology*; D005106:Exploratory Behavior / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D005787:Gene Frequency; D006580:Genetic Carrier Screening; D020022:Genetic Predisposition to Disease / Q000235:genetics / Q000523:psychology; D005838:Genotype; D006801:Humans; D008297:Male; D008694:Methamphetamine; D008875:Middle Aged; D009483:Neuropsychological Tests; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic / Q000235:genetics*; D011340:Problem Solving / Q000502:physiology*; D011594:Psychometrics; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D013694:Temperament; D014888:Wechsler Scales / Q000706:statistics & numerical data
D017448:Receptors, Dopamine D2; D008694:Methamphetamine