Tardive dyskinesia and DRD2, DRD3, DRD4, 5-HT2A variants in schizophrenia: an association study with repeated assessment.

We performed an association study between four candidate genes, DRD2, DRD3, DRD4 and 5-HT2A for the presence of tardive dyskinesia (TD) on 84 patients with residual schizophrenia. The sample was evaluated again for the presence of TD after an interval of 3 years. The first group did not exhibit TD in either observation (n=34) while in the second group of patients exhibited TD in at least one of the observations (n=20+18). The clinical and socio-demographic characteristics were not significantly different between the two groups; the genetic analysis revealed a significant correlation between the C/C genotype of 5-HT2A and TD (p=0.017). An association trend was observed between the 'short' variant of DRD4 and TD (p=0.022). We did not observe any significant association for the DRD2 and DRD3 polymorphisms.