Catechol-O-methyltransferase val108/158met genotype and response to antipsychotic medication in schizophrenia.

Catechol-O-methyltransferase (COMT) gene has been investigated as a possible candidate gene in schizophrenia. The most studied polymorphism has been the functional val108/158met polymorphism of this COMT gene. There is also some evidence that this polymorphism could be related to drug response to antipsychotics in schizophrenia. COMT enzyme inactivates dopamine and noradrenaline. Based mainly on the original dopamine theory of schizophrenia, our primary hypothesis was that the maintenance dose of antipsychotics would be higher in patients with the low activity COMT genotype. In this study we evaluated the current daily dosage of antipsychotics in 180 patients with schizophrenia in connection with the COMT genotype. We could not demonstrate any clearly significant effect of this particular COMT genotype in relation to the daily maintenance dosages of antipsychotics in patients with schizophrenia.