Genetic variation of GRIN1 confers vulnerability to methamphetamine-dependent psychosis in a Thai population.

•A cohort of male METH dependence with psychosis was genotyped for two SNPs in GRIN1.•G2108A SNP showed a very strong association with METH-induced psychosis.•These results identify a potential risk factor for drug-induced psychosis.•Genetic variation in glutamate system plays a role in the emergence of psychosis.