Serotonin 7 Receptor Variants Are Not Associated with Response to Second-Generation Antipsychotics in Japanese Schizophrenia Patients

Background: Individual differences in serotonin 7 receptor (5-HT7R) may result in variable response to antipsychotics with 5-HT7R antagonism. This study investigated the relationship between single nucleotide polymorphisms (SNPs) in the 5-HT7R gene (HTR7) and the efficacy of second-generation antipsychotic drugs with a high affinity for this receptor in Japanese schizophrenia. Methods: Perospirone or aripiprazole was administered to 100 patients with schizophrenia in a randomized controlled study. All patients were genotyped for three candidate SNPs (rs12412496, rs7916403, and rs1935349). Patient improvement on the Positive and Negative Syndrome Scale (PANSS) total score at 12 weeks was assessed as the primary outcome. PANSS 5-factor scores were investigated as the secondary outcome. Results: Improvement on the PANSS total score and genetic polymorphisms showed no correlation. The rs12412496-rs7916403-rs1935349 A-T-A haplotype was correlated with worse improvement in the cognition score (haplotype frequency: 0.285, p = 0.046, permuted p = 0.043). Conclusion: Our results show that HTR7 variants are not related to the overall improvement in schizophrenia symptoms.