·To investigate the therapeutic efficacy of metformin (MF) on glucose dysregulation and dyslipidaemia induced by quetiapine in patients with schizophrenia (SZ).

·A total of 83 SZ patients from Shanghai Hongkou District Mental Health Center and Shanghai Yangpu District Mental Health Center were enrolled, and randomly divided into treatment group (MF group, n=38) and control group (n=45). The control group received oral quetiapine therapy, and the MF group additionally received metformin on the basis of oral quetiapine therapy. The serum levels of glucose (GLU), total cholesterol (TC), triacylglycerol (TAG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), small density low-density lipoprotein cholesterol (sd-LDL-C) and homocysteine (HCY) were determined before treatment and 2, 4 and 8 weeks after treatment.

·There were no statistic differences in ages, courses, body mass index, the levels of GLU, TC, TAG, HDL-C, LDL-C, sd-LDL-C and HCY between the control and MF group before treatment (all P>0.05). After 8 weeks of treatment, levels of all biomarkers elevated in the control group. The levels of GLU, TC, TAG, LDL-C, sd-LDL-C and HCY were lower after treatment, and the level of HDL-C elevated higher in the MF group. The variations of levels of HDL-C after treatment showed statistically no significant difference between the two groups (P=0.247), while statistical differences existed in other biomarkers, which indicated that the glucose-lowering and lipid-lowering efficacies in the MF group were significantly better than those in the control group. The analysis of variance suggested that, in the control group, the level of HDL-C elevated significantly after 4 and 8 weeks′ treatment, having statistical differences (P=0.005 and P=0.003). The level of LDL-C elevated significantly after 2, 4 and 8 weeks′ treatment (P=0.005, P=0.019 and P=0.026), and no statistical differences were observed in other biomarkers. In the MF group, the levels of GLU, TC, TAG and sd-LDL-C were lower 2, 4 and 8 weeks after treatment, the levels of LDL-C and HCY descended 4 and 8 weeks after treatment, and no statistical differences were observed in other biomarkers. The level of HDL-C was higher after 2 weeks, treatment, but showed statistically no significant differences 4 and 8 weeks after treatment, compared to the level determined before treatment.

·Administration of MF in the SZ patients having glucose dysregulation and dyslipidaemia induced by quetiapine can significantly lower serum level of GLU, and improve the serum lipid profiles.