TABLE 1.

Summary of randomized trial literature

Study	Intervention	N	Findings
Berk et al21 (2008)	NAC 1 g twice daily vs placebo for 28 wk	140	In predominately clozapine- or olanzapine-treated patients with chronic schizophrenia: • PANSS negative scores improved, which was no longer evident at 4 wk post-NAC discontinuation • PANSS positive scores were not different between intervention groups • No effects on cognition were seen in the subset of subjects that received cognitive assessment
Farokhnia et al22 (2013)	NAC 1 g daily for 1 wk then twice daily vs placebo for 8 wk	42	Among inpatients concomitantly initiated on risperidone for treatment of active phase schizophrenia: • A significant improvement was seen in PANSS negative scores • No change found in PANSS positive scores • No assessment of cognition was performed
Sepehrmanesh et al23 (2018)	NAC 600 mg twice daily vs placebo for 12 wk	84	In patients with chronic schizophrenia but not managed on clozapine: • PANSS positive and negative scores were significantly improved • Improved cognitive assessment scores were noted

NAC = N-acetylcysteine; PANSS = Positive and Negative Syndrome Scale.