Meta-analysis of randomised controlled trials with N-acetylcysteine in the treatment of schizophrenia
What this study found
Adjunctive NAC showed a modest overall benefit, with the clearest effects on negative symptoms and total PANSS scores after longer treatment durations. At 24 weeks or longer, PANSS negative symptoms improved versus placebo (SMD = -0.41, p = 0.006) and PANSS total scores improved (SMD = -0.64, p < 0.001); across final timepoints, PANSS negative symptoms also favored NAC (SMD = -0.72, p = 0.003) and PANSS general symptoms were borderline (SMD = -0.34, p = 0.05). NAC also improved working memory across three studies (SMD = 0.56, p = 0.005), while processing speed did not differ significantly…
- Study & population
- Systematic review and meta-analysis of randomized controlled trials in people with schizophrenia or first-episode psychosis.
- Intervention
- N-acetylcysteine (NAC) was used as an adjunct to standard antipsychotic treatment in randomized placebo-controlled trials.
- Key limitation
- Interpretation is limited by heterogeneity across trials, relatively few studies, and variable reporting of demographics, safety, and secondary outcomes.
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Open PDFOriginal abstract
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.