The risk of psychotic symptoms in methamphetamine dependent individuals is eleven times higher as compared to the general population. Dopamine, which is one of the key neurotransmitters in etiopathogenesis of psychosis, is metabolised by catechol-O-methyltransferase (COMT).
The COMT gene Val158Met polymorphism changes activity of the COMT enzyme up to fourfold and thus influences the dopamine activity in the brain. The aim of the study was to ascertain whether subjects dependent individuals without psychosis in the Val158Met COMT genotype or allele frequency.