Dopamine D3 receptor gene not associated with symptomatology of major psychoses.

Dopamine D3 receptor gene (DRD3) variants have been implicated in the pathogenesis of psychiatric disorders. Many studies, however, have failed to replicate the association of DRD3 with schizophrenia. A possible reason for this may lie in the definition of phenotype, which is traditionally based on psychiatric diagnosis. In this study we investigated the possibility that variants of the DRD3 gene might be associated with symptomatology in a sample of subjects affected by major psychoses. Two hundred and eleven inpatients affected by major psychoses were assessed by the Operational Criteria Checklist for Psychotic Illness (OPCRIT) and were also typed for the DRD3 variants using polymerase chain reaction techniques. Mania, depression, delusion, and disorganization were the four symptomatologic factors used as phenotype definitions. DRD3 variants were not associated with these symptomatologic factors, and consideration of possible stratification effects, such as sex and psychiatric diagnosis, did not reveal any association either.