No evidence of association between Catechol-O-Methyltransferase (COMT) Val 158 Met genotype and performance on neuropsychological tasks in children with ADHD: A case-control study

Background Several studies have suggested an association between the functional Val158Met polymorphism in the Catechol-O-Methyltransferase (COMT) gene and neurocognitive performance. Two studies showed that subjects with the low activity Met allele performed better on the Wisconsin Card Sorting Test (WCST) and another study found an effect on processing speed and attention.