Zheng W, et al. - Authors undertook a systematic review and meta-analysis of randomized controlled trials (RCTs) to examine the efficacy and safety of adjunctive N-acetylcysteine (NAC), an antioxidant drug, in treating major depressive disorder (MDD), bipolar disorder, and schizophrenia. As per findings, adjunctive NAC appeared a safe treatment. For schizophrenia, this treatment seemed to be efficacious, but not for bipolar disorder or MDD.