DRD4 exon 3 genotype and ADHD: Randomised pharmacodynamic investigation of treatment response to methylphenidate.
|Title||DRD4 exon 3 genotype and ADHD: Randomised pharmacodynamic investigation of treatment response to methylphenidate.|
|Publication Type||Journal Article|
|Year of Publication||2017|
|Authors||Naumova D, Grizenko N, Sengupta SM, Joober R|
|Journal||World J Biol Psychiatry|
|Date Published||2017 Dec 15|
OBJECTIVES: Dopamine plays an important role in modulating attention and motor behaviours, dimensions altered in attention deficit/hyperactivity disorder (ADHD). Numerous association studies have linked dopamine receptor 4 (DRD4) to increased risk of ADHD. This study investigated the effect of DRD4 exon 3 polymorphism on child behaviours in response to treatment with methylphenidate.METHODS: A total of 374 children diagnosed with ADHD (ages 6-12 years) were evaluated under three experimental conditions: baseline, placebo and MPH (0.5 mg/kg/day). This was a 2-week prospective within-subject, placebo-controlled, crossover trial. The Conners' Global Index for parents and for teachers was used to evaluate the behaviours of the children. One-way repeated measures analysis of variance was used to test the effect of the interaction between DRD4 genotype and experimental conditions.RESULTS: A significant interaction between DRD4 genotype and treatment was detected when the child's behaviour was evaluated by the parents (P = 0.035, effect size of 0.014), driven by a better treatment response in children homozygous for long 7-repeat allele.CONCLUSIONS: According to the parent assessment, children homozygous for the long 7-repeat allele were more responsive to experimental condition. This is the largest pharmacogenetic investigation of the effect of DRD4 exon 3 polymorphism in childhood ADHD.TRIAL REGISTRATION: clinicaltrials.gov, identifier NCT00483106.
|Alternate Journal||World J. Biol. Psychiatry|