BDNF and schizophrenia: Serum levels of GDNF and BDNF were significantly lower in patients with schizophrenia compared to healthy controls at baseline (GDNF: 304.838 ± 18.236 pg/ml vs. 378.534 ± 24.397 pg/ml, p = 0.012; BDNF: 275.821 ± 21.447 pg/ml vs. 370.983 ± 33.849 pg/ml, p = 0.010).