Haukur Pálmason

• The catechol-O-methyltransferase gene (COMT) plays a crucial role in the metabolism of catecholaminesrnin the frontal cortex. A single nucleotide polymorphism (Val158Met SNP, rs4680) leads to eitherrnmethionine (Met) or valine (Val) at codon 158, resulting in a three- to fourfold reduction in COMT activity. The aim of the present study was to assess the COMT Val158Met SNP as a risk factor for attention-deficit/hyperactivity disorder (ADHD), ADHD symptom severity and co-morbid conduct disorder (CD) in 166 children with ADHD. The main finding of the present study is that the Met allele of the COMT Val158Met SNP was associated with ADHD and increased ADHD symptom severity. No association with co-morbid CD was observed. In addition, ADHD symptom severity and early adverse familial environment were positive predictors of lifetime CD. These findings support previous results implicating COMT in ADHD symptom severity and early adverse familial environment as risk factors for co-morbid CD, emphasizing the need for early intervention to prevent aggressive and maladaptive behavior progressing into CD, reducing the overall severity of the disease burden in children with ADHD.
• Aufmerksamkeitsdefizit-Hyperaktivitätsstörung (ADHS) beeinflusst das Leben von etwa 5 % aller Schulkinder.In dieser Arbeit wurde die Interaktion zwichen Umweltsfaktoren und ein Einzelnukleotid-Polymorphismen in dem Katechol-O-Methyl-Transferase (COMT) Gene in ADHS Kinder untersucht. Dieser Studie konnte zeigen, dass der Polymorphism assoziiert mit ADHS war, rauchen im Schwangerschaft führten zu mehr schwieriger ADHS symptomatik und negativen Familien Verhältnisse erhöhen die Risiko für komorbid Verhaltensstörung.