title: Relationship among methadone dose, polymorphisms of dopamine D2 receptor and tri-dimensional personality questionnaire in heroin-addicted patients.
abstract: BACKGROUND
  We investigated whether variation in the dopamine D2 receptor gene (DRD2) and tri-dimensional personality questionnaire (TPQ) scores could be used to aid adjustment of daily methadone requirements of heroin addicts. DRD2 TaqI B polymorphisms and TPQ scores were determined in 138 male Taiwanese heroin addicts who were receiving methadone treatment. Borderline index (harm avoidance + novelty seeking-reward dependence) was calculated for each subject, and three groups were defined: high (mean from all subjects plus 1 standard deviation, or greater), low (half of the calculated high score, or lower) and medium (all values between the high and low scores).
  
  
  RESULTS
  No significant differences in age (p = 0.60), mean methadone dose (p = 0.75) or borderline index group (p = 0.25) were observed between subjects bearing the B1/B1, B1/B2 and B2/B2 DRD2 TaqI genotypes. Among the individuals with low (≤10), medium (11-20) and high (≥21) borderline index scores, there was a significant difference in mean methadone dose (p = 0.04), but not age (p = 0.90). Further analysis showed that mean methadone dose was significantly higher in subjects with low borderline index scores than in those with high scores (62.5 vs. 47.0 mg/day, p = 0.03). The odds ratio for a daily methadone requirement ≥60 mg (median dose across the 138 subjects) was 2.64-fold greater in the low borderline index group than in the high group (p = 0.04).
  
  
  CONCLUSIONS
  Although the DRD2 TaqI B genotype was not associated with methadone use requirements, borderline index was revealed as a potential predictive marker for the adjustment of methadone dosage requirements in heroin addicts.
authors: Department of Psychiatry, Chia-Yi Branch, Taichung Veterans General Hospital, Chiayi, Taiwan.|General Education Center, Taiwan Shoufu University, Tainan, Taiwan.
authors: Min-Wei
authors: MW
authors: Huang
authors: College of Medicine and Life Science, Chung Hwa University of Medical Technology, Tainan, Taiwan.
authors: Tai-An
authors: TA
authors: Chiang
authors: Institute of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan.
authors: Pei-Yu
authors: PY
authors: Lo
authors: Administration Center of Research and Education Innovation, Changhua Christian Hospital, Changhua, Taiwan. ching.shan.h@gmail.com.
authors: Ching-Shan
authors: CS
authors: Huang
mesh_terms: D000328:Adult; D004305:Dose-Response Relationship, Drug; D005787:Gene Frequency; D005838:Genotype; D003932:Heroin; D006556:Heroin Dependence / Q000235:genetics; D006801:Humans; D008297:Male; D008691:Methadone / Q000378:metabolism* / Q000494:pharmacology; D008875:Middle Aged; D010551:Personality; D010552:Personality Assessment; D011110:Polymorphism, Genetic / Q000235:genetics; D017448:Receptors, Dopamine D2 / Q000187:drug effects / Q000235:genetics*; D019966:Substance-Related Disorders; D011795:Surveys and Questionnaires; D013624:Taiwan
chemical_list: C581293:DRD2 protein, human; D017448:Receptors, Dopamine D2; D003932:Heroin; D008691:Methadone
keywords: Borderline index; DRD2; Heroin-dependent patients; Methadone requirement; TPQ