Dopamine receptor D2 Ser/Cys 311 variant is associated with delusion and disorganization symptomatology in major psychoses

The D2 receptor (DRD2) is a binding site of many psychoactive drugs and it has been proposed as a genetic risk factor for psychiatric disorders. The a im of this investigation was to study the DRD2 S311C variant in major psych oses. We studied 1182 inpatients with diagnoses of bipolar disorder (n = 48 0), major depressive disorder (n = 269), schizophrenia (n = 366), delusiona l disorder (n = 44), psychotic disorder not otherwise specified (n = 23) an d 267 healthy controls. Eight hundred and eighty-seven subjects were also s cored for their lifetime symptomatology using the the Operational Criteria checklist for psychotic illness (OPCRIT), DRD2 variants were not associated with affected subjects even when possible confounders like gender and onse t were considered. When we considered the 887 subjects with the symptomatol ogic analysis, we observed a significant association of the DRD2 S311C vari ant with both delusion and disorganization features. The association was pr esent independently from diagnoses. Our results do not show that coding var iants of the DRD2 S311C play a major role in conferring susceptibility to m ajor psychoses, but they may be connected with disorganized and delusional symptomatology independently from diagnoses.