COMT and MTHFR polymorphisms interaction on cognition in schizophrenia: An exploratory study

► COMT (rs4680) and MTHFR (rs1801133) enzyme genes are related with cognition. ► Their interaction in schizophrenia has not been adequately investigated. ► It is unknown whether dopamine interacts with methylation mechanisms on cognition. ► We found that COMT and MTHFR interacted on working memory and planning. ► MTHFR hypofunction likely attenuates the cognitive effects of COMT hyperfunction.