TY - THES A1 - Pálmason, Haukur T1 - The effects of catechol-O-methyltransferase (COMT) and psychosocial risk factors on symptom severity and co-morbid Conduct Disorder in Attention-Deficit/Hyperactivity Disorder N2 - The catechol-O-methyltransferase gene (COMT) plays a crucial role in the metabolism of catecholamines in the frontal cortex. A single nucleotide polymorphism (Val158Met SNP, rs4680) leads to either methionine (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. KW - Aufmerksamkeits-Defizit-Syndrom KW - Catecholmethyltransferase KW - Verhaltensstörung KW - SNP KW - (ADHD KW - Birth weight KW - Conduct disorder KW - COMT Val158Met KW - Smoking) Y1 - 2009 UR - https://ubt.opus.hbz-nrw.de/frontdoor/index/index/docId/356 UR - https://nbn-resolving.org/urn:nbn:de:hbz:385-5629 ER -