(4) Results: The review considers candidate genes encoding dopamine receptors involved in pharmacodynamics, including genes DRD1, DRD2, DRD3, and DRD4. We analyzed 18 genome-wide studies examining 37 genetic variations, including single nucleotide variants (SNVs)/polymorphisms of four candidate genes involved in the development of AIP and AITD in patients with schizophrenia. The gene discussed is DRD3; the disease is autoimmune pancreatitis.