Serum BDNF levels, glycolipid metabolism in deficit schizophrenia: A case-control study

Few studies have compared serum BDNF and glycolipid profiles in patients with deficit schizophrenia (DS) and non-deficit schizophrenia (NDS). We aimed to compare BDNF and glycolipid profiles between DS and NDS patients and healthy controls, and to investigate the relationship between BDNF, glycolipid profiles in DS and NDS patients.

A total of 591 patients with chronic schizophrenia (SZ) and 238 healthy controls participated in this study. According to Proxy for the Deficit Syndrome Scale, SZ patients were divided into DS (n = 158) and NDS (n = 273) patients. Psychiatric symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS). Serum BDNF levels were measured using enzyme-linked immunosorbent assay (ELISA).

BDNF levels were significantly lower in SZ patients than those in healthy controls (7.81 ± 2.98 ng/ml vs. 11.96 ± 2.29 ng/ml, P < 0.01). Furthermore, BDNF levels were lower in DS group than those in NDS group (P = 0.007, OR = 0.846, 95% CI = 0.750-0.955). Lower triglyceride levels were also an independent predictor for DS patients (P = 0.007, OR = 0.846, 95% CI = 0.750-0.955). Serum BDNF levels were negatively associated with the severity of deficit syndrome in SZ patients (β = -1.151, t = -2.559, P = 0.011). In DS group, triglycerides were associated with PANSS negative subscore (β = -0.262, t = -2.994, P = 0.003) and depressive factor subscore (β = 0.282, t = 2.146, P = 0.035).

Serum BDNF and triglycerides may be informative biomarkers of DS in SZ patients. The differences in glycolipid metabolism patterns between DS and NDS patients indicate that deficit syndrome is an independent endophenotype of SZ patients.