Influence of genetic variability at the COMT gene on TMT-B performance in psychotic patients and their healthy siblings

Abstract

The Val158Met catechol-O-methyl transferase functional polymorphism has been repeatedly associated to differences in performing the Wisconsin Card Sorting Test in both, patients with schizophrenia and healthy individuals. However, this association has not been consistently replicated for the Trail Making Test part-B (TMT-B). In a sample of 89 patients suffering from a functional psychotic disorder and their healthy siblings we aim (i) to explore if there is any difference completing the TMT-B between both groups and among the different psychotic categories, and (ii) to investigate the association between the catechol-O-methyl transferase genotype and the TMT-B performance. Psychotic patients executed the TMT-B worse than the siblings group (P≤0.006). The patients (P=0.001) and the siblings (P=0.006) with the Val/Val genotype used more time to execute the test than those who carried the Met allele.