Effects of NAC on Symptoms of CHR Patients

The primary aim is to examine the effect of NAC on psychosis-like symptoms in CHR patients. Secondary aims are to examine the effect of NAC, in these patients, on the amplitude of the mismatch negativity (MMN), an electroencephalographic event-related potential (ERP) response to rare sounds among frequent ones; and the amplitude of the N400 semantic priming effect, an ERP response to unexpected compared to expected meaningful stimuli (e.g., words, pictures); both of which have been found to be reduced in both schizophrenia and the CHR state. This will be a randomized, double-blind, placebo-controlled trial. Ninety CHR patients will take either NAC 2000 mg orally or placebo, daily for 8 weeks. Psychosis-like symptoms will be assessed at baseline, week 4 and week 8 using the Positive symptom score of the Scale of Psychosis-Risk Symptoms in the Structured Interview for Psychosis-Risk Syndromes. MMN amplitude and the N400 semantic priming effect will be measured at baseline and week 8. We hypothesize that patients will have more improvement in psychosis-like symptoms, and greater increases in MMN amplitudes and N400 semantic priming effects, after taking NAC vs. placebo. If we find that NAC improves psychosis-like symptoms and/or these neurophysiological biomarkers of the CHR state, this would support further research on NAC as a preventive treatment against psychosis.