Meta-analysis of randomised controlled trials with N-acetylcysteine in the treatment of schizophrenia

• Published in: Australian and New Zealand journal of psychiatry 2020-05, Vol.54 (5), p.453-466
• Main Authors: Yolland, Caitlin OB, Hanratty, Donal, Neill, Erica, Rossell, Susan L, Berk, Michael, Dean, Olivia M, Castle, David J, Tan, Eric J, Phillipou, Andrea, Harris, Anthony WF, Barreiros, Ana Rita, Hansen, Abigail, Siskind, Dan
• Format: Article
• Language: English
• ISSN: 0004-8674; 1440-1614
• DOI: 10.1177/0004867419893439

Objective: There is accumulating evidence that adjunctive treatment with N-acetylcysteine may be effective for schizophrenia. This study aimed to conduct a comprehensive meta-analysis examining the efficacy of randomised control trials investigating N-acetylcysteine as an adjunct treatment for schizophrenia and the first to investigate cognition as an outcome. Methods: We systematically reviewed Medline, EmCare, PsycINFO, Embase, CINAHL Complete, China Knowledge Resource Integrated Database and the Cochrane Clinical Trials online registry for randomised control trials of N-acetylcysteine for schizophrenia. We undertook pairwise meta-analyses of N-acetylcysteine vs placebo for psychosis symptoms and cognition. Results: Seven studies, including n = 220 receiving N-acetylcysteine and n = 220 receiving placebo, met inclusion criteria for the pairwise meta-analyses. Positive and Negative Syndrome Scale negative and total scores were significantly improved in the N-acetylcysteine group after 24 weeks of treatment. The cognitive domain of working memory improved with N-acetylcysteine supplementation. Conclusion: Evidence supports the notion that N-acetylcysteine may be a useful adjunct to standard treatment for the improvement of schizophrenia symptoms, as well as the cognitive domain of working memory. Treatment effects were observed at the later time point (⩾24 weeks), suggesting that longer interventions are required for the success of N-acetylcysteine treatment.