Liver enzymeCYP2D6gene and tardive dyskinesia

Background:Tardive dyskinesia (TD) is an iatrogenic involuntary movement disorder occurring after extended antipsychotic use with an unclear pathogenesis.CYP2D6is a liver enzyme involved in antipsychotic metabolism and a well-studied gene candidate for TD.Materials & methods:We tested predicted CYP2D6 metabolizer phenotype with TD occurrence and severity in our two samples of European chronic schizophrenia patients (total n = 198, of which 82 had TD).Results:TD occurrence were associated with extreme metabolizer phenotype, controlling for age and sex (p = 0.012). In other words, individuals with either increased and no CYP2D6 activity were at higher risk of having TD.Conclusion:Unlike most previous findings, TD occurrence may be associated with both extremes of CYP2D6 metabolic activity rather than solely for poor metabolizers.