307. THE EFFECT OF SODIUM BENZOATE TREATMENT FOR TREATMENT RESISTANT SCHIZOPHRENIA AND ITS ASSOCIATION WITH GLUTAMATE CONCENTRATION: A PILOT STUDY WITH PROTON MAGNETIC RESONANCE SPECTROSCOPY

Abstract Background Glutamatergic system has been proposed as a potential therapeutic mechanism for patients with treatment resistant schizophrenia (TRS) whose treatment response is poor to the dopaminergic agents. Sodium benzoate (SB) is a D-amino acid oxidase inhibitor, could be a treatment choice for schizophrenia via glutamatergic system. Aims & Objectives The aims of present study are to test whether SB will bring symptoms improvement and benefit effect on the cognitive function among patients with TRS, and to probe the association between the concentration of glutamate in the anterior cingulate cortex and the effect of SB treatment. Method A total of 18 patients with TRS were randomly assigned to 6-week treatment with SB (N = 12) or placebo (N = 6). The symptoms (PANSS) severity and cognitive function (working memory, sustained attention) were probed at the baseline, week 2, and week 6. The glutamate concentration was probed by the proton magnetic resonance spectroscopy (1H-MRS) with 1.5T scanner. Results Reductions on the positive (week 2: Z = 2.46, P = 0.01; week 6: Z = 2.24, P = 0.03), negative (week 2: Z = 2.16, P = 0.03), and general (week 2: Z = 2.08, P = 0.04; week 6: Z = 2.81, P = 0.01) symptoms were found at week 2 and week 6 among patients receiving SB. For patients receiving placebo, the reductions of symptoms (positive and negative) were found only at week 6. The improvement of the working memory (Week 2: Z = 2.25, P = 0.03; week 6: Z = 2.14, P = 0.03) and attention (week 2: Z = 2.05, P = 0.04; week 6: Z = 2.49, P = 0.01) was found in SB subgroup. The glutamate concertation at the baseline is positively related with the reduction of negative symptoms (r = 0.72, p = 0.04) at the week 2 among patients receiving SB. Discussion & Conclusions The efficacy of SB for the earlier response of schizophrenia was found. The 1H-MRS glutamate concentration might be a predictor for treating with SB for patients with TRS.