atechol-O-Methyltransferase (COMT) Genotypes nd Working Memory: Associations with Differing ognitive Operations

ackground: Catechol-O-methyltransferase (COMT) is a strong candidate gene for schizophrenia and cognitive functions disrupted n this disorder. This report examines the relation of COMT genotypes to performance on a battery of working memory tests differing n the cognitive operations to be performed on the material. ethods: A large sample of 402 healthy adults were tested on four working memory tests: Spatial Delayed Response (SDR), Word Serial osition Test (WSPT), N-back, and Letter–Number Sequencing. A subsample (n 246) was tested on the Wisconsin Card Sorting Test WCST). A saliva swab was used to obtain DNA from all participants. esults: Letter–Number Sequencing, which requires both storage and manipulation of information, was the only working memory test hat showed expected differences among COMT genotypes, with the met/met group showing the best performance and the val/val group he poorest performance. As in previous studies, the met/met group also performed better than the val/val group on the WCST. onclusions: COMT genotypes were not associated with performance on tests measuring simple storage, maintenance of temporal rder or updating of information in working memory. Genotype differences in Letter–Number Sequencing and WCST suggest that igher-order components of processing (e.g., mental manipulation) are more closely related to this gene.