Pharmacogenetics of treatment in first-episode schizophrenia: D3 and 5-HT2C receptor polymorphisms separately associate with positive and negative symptom response

We have been studying the pharmacogenetic correlates of side effects and early response to antipsychotic treatment in a series of Chinese Han first-episode drug-naïve patients with schizophrenia. Here, we report the association of three functional polymorphisms of receptor genes on initial symptom severity and outcome in these patients. We studied the dopamine D3 receptor ser9gly, the dopamine D2 receptor Taq IA and the 5-HT2C receptor promoter −759C/T polymorphisms in 117 patients who had symptoms assessed by Positive and Negative Syndrome Scale (PANSS) on admission and following 10-week antipsychotic treatment, primarily with risperidone or chlorpromazine. The D2 polymorphism was found not to be significantly associated with baseline levels or changes in total PANSS in these patients. The D3 genotype is associated with the change in total PANSS ( p