PANSS N subscale scores did not differ significantly between SZ+T2DM vs. SZ−T2DM groups (20.80 ± 6.64 vs. 21.84 ± 7.16, respectively).SZ+T2DM had superior cognitive performance and higher BDNF levels than SZ−T2DM. This evidence concerns the gene BDNF and type 2 diabetes mellitus.