Genetic variants of dopamine receptor D4 and psychopathology

There is much evidence to indicate that the dopamine receptor D4 (DRD4) gen e is involved in psychiatric disorders. We investigated the correlation bet ween DRD4 gene polymorphism and the psychopathology of major psychoses, ind ependently of diagnoses. Some 461 inpatients affected by major psychoses we re assessed by the Operational Criteria checklist for psychotic illness and typed for DRD4 variants. The four symptomatologic factors-mania, depressio n, delusion, and disorganization-were used as phenotype definitions, DRD4 E xon 3 long allele variants were associated with high delusional scores, wit h the most significant difference between alleles 2 and 7 (p = 0.004). DRD4 variants may, therefore, constitute a liability factor for development of delusional symptomatology in patients with major psychoses.