Association of the COMT and DRD2 Genes with the Ability of Schizophrenia Patients to Understand the Mental State of Other People

Abstract

With the aim of identifying the role of dopamine transmission in impairments to the ability of schizophrenia patients to understand the mental state of other people, we searched for associations between this component of social cognition and genes encoding the DRD2 receptor and the enzyme COMT in 209 schizophrenia patients and 172 healthy people. Neuropsychological assessment of subjects consisted of solving verbal tasks involving second-order false beliefs (FB2) and assessment of the ability to detect faux pas. An association was found between the Val158Met polymorphism of the COMT gene and success in solving FB2 tasks by schizophrenia patients. This association was linked with sexual dimorphism. Impairments were seen in female patients carrying the Met allele. In male patients, a tendency to more marked impairment was linked with the ValVal genotype. Analysis of correlations between the COMT Val158Met marker and the ability to solve FB2 tasks and neurocognitive and clinical symptoms suggested that the association detected in female patients was mediated, at least partly, by increased stress reactivity in carriers of the Met allele due to the acuteness of patients’ status and its consequences for cognitive functioning.