Therefore, the main objectives of this study were to (1) compare serum levels of NGF-β, BDNF, and 1,25(OH)2D between male patients with chronic schizophrenia and healthy controls; (2) investigate the relationships among NGF-β, BDNF, and 1,25(OH)2D levels and psychopathological symptoms and cognitive deficits; (3) explore potential associations among NGF-β, BDNF, and 1,25(OH)2D; and (4) evaluate NGF-β, BDNF, and 1,25(OH)2D levels as potential risk factors for chronic schizophrenia. This evidence concerns the gene BDNF and Cognitive impairment.