tokens: METHODS : We identified seven SNP ( single nucleotide polymorphism ) ( - 141Cins > del , TaqIB , TaqID , Ser311Cys , rs6275 , rs6277 and TaqIA ) in the DRD2 gene in 146 schizophrenic inpatients ( 59 with EPS and 87 without EPS according to the Simpson - Angus Scale ) treated with chlorpromazine after 8 weeks .