Prolactin levels in antipsychotic treatment of patients with schizophrenia carrying the DRD2*AI allele

Abstract

Background: Hyperprolactinaemia induced by D2 dopamine receptor antagonist antipsychotic medication can result in significant health problems. Aims: To examine the role of DRD2 polymorphism on prolactin levels in patients treated with antipsychotic medication. Method: Antipsychotic drugs with different degrees of D2 receptor binding were given to 144 patients with schizophrenia. Serum prolactin levels were obtained and TaqIA DRD2 alleles were determined. Results: Prolactin levels increased across medication groups reflecting increasingly tight D2 receptor binding (clozapine, olanzapine, typical antipsychotics and risperidone). In the combined medication group, patients with the DRD2*AI allele had 40% higher prolactin levels than patients without this allele. In patients treated with clozapine (the loosest D2 receptor binding agent), patients with the DRD2*AI allele had prolactin levels twice those of patients without this allele. Conclusions: Patients with the DRD2AI allele receiving antipsychotic medications had higher prolactin levels and were overrepresented among those with hyperprolactinaemia, suggesting greater functional D2 receptor binding in this group.