COMT and schizophrenia: Regarding genetic models, we assessed an association of symptoms in schizophrenia with COMT rs4680 or COMT 4818 polymorphisms using genotypic, allelic, dominant (AA + GA vs. GG for COMT rs4680 and CG + GG vs. GG for COMT rs4818) and recessive (AA vs. GA + GG for COMT rs4680 and CC vs. CG + GG for COMT rs4818) models, respectively.