주의력결핍 과잉행동장애 아동에서 Methylphenidate 투여 전후 [123I]IPT SPECT로 측정한 기저 신경절 Dopamine Transporter Density

Abstract

Objectives : ADHD has been known as psychiatric disorder in childhood associated with dopamine dysregulation. The symptoms of ADHD can be treated with methylphenidate, a potent blocker of the dopamine transporter (DAT). In present study, we investigated DAT density using I-123N-(3-iodopropen-2-yl)-2β-carbomethoxy-3beta-(4-chlorophenyl) tropane ([123I]IPT SPECT) in children with ADHD before and after treatment with methylphenidate. Methods : Seven drug-naive children with ADHD and eight normal children were included in the study and performed SPECT 2 hours after an intravenous administration of[123I]IPT. All children with ADHD reperformed [123I]IPT SPECT after treatment with methylphenidate (0.7 mg/kg/d) during about 8 weeks. SPECT data reconstructed for the assessment of specific/nonspecific DAT binding ratio of the basal ganglia were compared between before and after treatment methylphenidate. We investigated correlation between the change of ADHD symptom severity assessed with ADHD rating scale-IV and specific/nonspecific DAT binding ratio of basal ganglia. Results : Children with ADHD had a significantly greater increase of specific/nonspecific DAT binding ratio of right basal ganglia than normal children (Right : z=2.085, p=0.037 ; Left : z=1.506, p=0.132). Under treatment with methylphenidate in all children with ADHD, specific/nonspecific DAT binding ratio of both basal ganglia decreased significantly greater than before treatment with methylphenidate (Right : t=3.239, p=0.018 ; Left t=3.133, p=0.020). However, no significant correlation between the change of ADHD symptom severity scores and specific/nonspecific DAT binding ratio of the basal ganglia were found. Conclusions : The data of this study using methylphenidate in children with ADHD support the complex dysregulation of the dopaminergic neurotransmitter system in children with ADHD.