NTF3 and schizophrenia: Examination of the polymorphisms of six genes, D2 and D3 DA receptors, serotonin A2 receptor, the brain-derived neurotrophic factor, ciliary neurotrophic factor and neurotrophin-3, showed that there are significant differences between patients with schizophrenia and a control group regarding the D2 receptor gene in all patients, and D2 and neurotrophin-3 in female patients.