Allele frequencies of dopamine D4 receptor gene (DRD4) and Catechol-O-methyltransferase (COMT) Val158Met polymorphism are associated with methylphenidate response in adolescents with attention deficit/hyperactivity disorder: a case control preliminary study

Figures & data

Table 1. Allele frequencies of the DRD4, and COMT polymorphisms in patients with ADHD and controls.

Polymorphic sites	DRD4 48 bp VNTR				COMT Val158Met
Genotype	7+	7−	4+	4−	Met/Met	Met/Val	Val/Val
ADHD
n (total 20)	9	25	29	5	4	17	13
Frequency (%)	26	74	85	15	12	50	38
Control
n (total 50)	16	34	47	3	10	20	20
Frequency (%)	32	68	94	6	20	40	40

Table 2. ARS and CGI Scales at pre-treatment and rating scales after two months OROS-methylphenidate treatment.

	Pre-treatment	Post-treatment	p
ARS total	36.09 ± 8.25	18.57 ± 8.89	<.001
ARS inattention/hyperactivity	20.73 ± 3.89	11.21 ± 5.27	<.001
ARS impulsivity /Hyperactivity	15.12 ± 6.18	7.36 ± 4.62	<.001
CGI	5.18 ± 0.72	3.45 ± 1.09	<.001

Notes: p values determined by paired sample t-test. Bold values indicate statistically significant results. ARS: DuPaul Rating Scale; CGI: Clinical Global Impression.