SA19. N-Acetyl-Cysteine in a Double-Blind Randomized Placebo-Controlled Trial: Toward Biomarker-Guided Treatment in Early Psychosis

Background: Biomarker-guided treatments are needed in psychiatry and previous data suggest redox dysregulation / oxidative stress may be a target in schizophrenia (1,2). A previous add-on trial with the antioxidant N -Acetyl-Cysteine (NAC) led to negative symptoms reductions in chronic patients (3). We aim to study NAC impact on symptoms and neurocognition in early psychosis (EP) and to explore whether glutathione (GSH)/redox markers could represent valid biomarkers to guide treatment. Methods: In a double-blind, randomized, placebo-controlled trial in 63 EP patients, we assessed the effect of NAC supplementation (2700 mg/day, 6 months) on PANSS, neurocognition (MATRICS Consensus Cognitive Battery [MCCB]), and redox markers (brain GSH [GSH-mPFC], blood cells GSH [GSH-BC] levels, and GSH peroxidase activity [GPx-BC]). Results: No changes in negative, positive symptoms, or functional outcome were observed with NAC, but significant improvements were found in favor of NAC on the MCCB Processing Speed factor and two of its components: Trail Making and Verbal Fluency. NAC leads to increases in GSH-mPFC by 23% ( P = .005) and GSH-BC by 19% ( P = .05). In patients with high-baseline GPx-BC (>22.3U/gHb), subgroup explorations revealed an improvement with NAC of positive symptoms when compared to patients with low-baseline GPx ( P = .02), with an improvement of positive symptoms in parallel with that of the redox status. Conclusion: In conclusion, NAC supplementation in a limited sample of EP patients did not improve negative symptoms, which were at modest levels at baseline. However, NAC leads to neurocognition improvement as well as to brain GSH levels increases, pointing to good target engagement. Blood GPx activity, a redox peripheral index associated with brain GSH levels, could help to identify a subgroup of patients who improve their positive symptoms with NAC. Future trials with antioxidant in EP should consider biomarker-guided treatment. References 1. Steullet P et al. 2016, Redox dysregulation, neuroinflammation, and NMDA receptor hypofunction: A “central hub” in schizophrenia pathophysiology? Schizophr Res. 176:41. 2. Hardingham GE, Do KQ, 2016, Linking early-life NMDAR hypofunction and oxidative stress in schizophrenia pathogenesis. Nat Rev Neurosci. 17:125. 3. Berk M et al. 2008, N-acetyl cysteine as a glutathione precursor for schizophrenia--a double-blind, randomized, placebo-controlled trial. Biol Psychiatry, 64:361.