No significant association between SIRT1 gene and methamphetamine-induced psychosis in the Japanese population

Objectives: We previously showed that the sirtuin 1 gene (SIRT1 gene), one of the clock genes, was associated with schizophrenia in a Japanese patient population. Because the symptoms of methamphetamine (METH)-induced psychosis are similar to those of paranoid type schizophrenia and because not every METH user develops psychosis, it is conceivable that METH-induced psychosis and schizophrenia have common susceptibility genes. Therefore, we conducted an analysis of the association of SIRT1 gene with METH-induced psychosis, hypothesizing a significant relationship. Methods: This paper presents a case-control study of the SIRT1 gene in 515 Japanese individuals (197 with METH-induced psychosis and 318 age-matched and sex-matched controls) with four tagging single nucleotide polymorphisms (rs12778366, rs2273773, rs4746720, and rs10997875), selected a priori using the HapMap database. Results: rs10997875 (located in the 3′ flanking region) was associated with METH-induced psychosis (unadjusted p_genotype=0.0203). However, these results became non-significant after Bonferroni correction (corrected p _genotype=0.0812). In the all-marker haplotype analysis, the SIRT1 gene was not associated with METH-induced psychosis (p=0.146). Conclusion: Our findings suggest that SIRT1 gene does not contribute to the development of METH-induced psychosis in the Japanese population. However, a replication study using larger samples should be conducted to obtain conclusive results.