Does COMT genotype influence the effects of d‐amphetamine on executive functioning?. (29th December 2012)

• Record Type: Journal Article
• Authors: Wardle, M. C.; Hart, A. B.; Palmer, A. A.; de Wit, H.
• Is Part Of: Genes, brain, and behavior. Volume 12:Number 1(2013:Feb.)
• Page Start: 13
• Page End: 20
• Publication Date: 2012-12-29
• Subjects: COMT genotype -- d‐amphetamine -- executive functioning -- genetics -- stimulant response -- working memory; Behavior genetics -- Periodicals; Neurogenetics -- Periodicals; 616.8
• DOI: 10.1111/gbb.12012
• Languages: English
• ISSNs: 1601-1848

Abstract

Abstract : In a widely cited study, Mattay et al . reported that amphetamine (0.25 mg/kg oral, or 17 mg for a 68 kg individual) impaired behavioral and brain indices of executive functioning, measured using the Wisconsin Card Sorting Task (WCST) and N‐Back working memory task, in 6 individuals homozygous for the met allele of the val158met polymorphism in the catechol‐ O ‐methyltransferase ( COMT ) gene, whereas it improved executive functioning in 10 individuals homozygous for the more active val allele. We attempted to replicate their behavioral findings in a larger sample, using similar executive functioning tasks and a broader range of amphetamine doses. Over four sessions, n = 200 healthy normal adults received oral placebo, d ‐amphetamine 5, 10, and 20 mg (average of 0.07, 0.15 and 0.29 mg/kg), under counterbalanced double‐blind conditions and completed WCST and N‐back tests of executive functioning. Amphetamine had typical effects on blood pressure and processing speed but did not affect executive functioning. COMT genotype (val158met) was not related to executive functioning under placebo or amphetamine conditions, even when we compared only the homozygous val/val and met/met genotypes at the highest dose of amphetamine (20 mg). Thus, we were not able to replicate the behavioral interaction between COMT and amphetamine seen in Mattay et al . We discuss possible differences between the studies and the implications of our findings for the use of COMT genotyping to predict clinical responses to dopaminergic drugs, and the use of intermediate phenotypes in genetic research. Abstract : Failure to replicate Mattay et al . (2003). COMT did not moderate effects of amphetamine on executive functioning (WCST perseverative errors).