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RETRACTED ARTICLE: Effect of N-acetyl cysteine (NAC) supplementation on positive and negative syndrome scale in schizophrenia: a systematic review and meta-analysis of randomised controlled trials

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This article was retracted on 11 April 2019

This article has been updated

Abstract

Objective

To conduct a systematic review and meta-analysis of published randomised controlled trials on the efficacy of NAC supplementation on positive and negative syndrome scale in schizophrenia.

Methods

A meta-analysis was conducted, and studies were identified by a search of electronic databases from inception to May 2018. Combined and stratified analyses were used.

Results

Seven trials were identified, and data from n = 447 participants were included. Pooled analysis showed improvement of positive and negative syndrome scale following NAC treatment compared with placebo, for total (SMB = − 0.96) [95% CI − 1.69, − 0.24; P = 0.009], general (SMB = − 1.04) [95% CI − 1.80, − 0.27; P = 0.008] and negative (SMB = − 0.73) [95% CI − 1.29, − 0.17; P = 0.01] scores, respectively. Significant heterogeneity was found, and subgroup analysis showed significant reductions in studies with a treatment duration of ≤ 24 weeks, with a considerable effect size on total, general, and negative scores (Total SMD = − 0.83; General SMD = − 0.67; Negative SMD = − 1.09) following NAC.

Conclusions

NAC improved all aspects of positive and negative syndrome scale in schizophrenic populations and may be more efficacious with treatment durations up to 24 weeks.

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Change history

  • 11 April 2019

    The authors have retracted this article [1] because there are fundamental errors in the data presented that undermine the conclusions drawn. All authors agree with this retraction. The authors are re-analysing their data and intend to submit a new manuscript for peer review in due course.

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Author information

Authors and Affiliations

  1. Department of Addiction Studies, School of Medicine, Kashan University of Medical Sciences, Kashan, Iran

    Amir Ghaderi

  2. Department of Psychiatry, School of Medicine, Kashan University of Medical Science, Kashan, Iran

    Amir Ghaderi

  3. Applied Health and Social Care, Faculty of Health and Social Care, Edge Hill University, Ormskirk, Lancashire, UK

    Anna Bussu & Catherine Tsang

  4. Research Center for Biochemistry and Nutrition in Metabolic Diseases, Kashan University of Medical Sciences, Kashan, Iran

    Sadegh Jafarnejad

Authors
  1. Amir Ghaderi
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  2. Anna Bussu
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  3. Catherine Tsang
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  4. Sadegh Jafarnejad
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Corresponding author

Correspondence to Sadegh Jafarnejad.

Additional information

The authors have retracted this article because there are fundamental errors in the data presented that undermine the conclusions drawn. All authors agree with this retraction. The authors are re-analysing their data and intend to submit a new manuscript for peer review in due course.

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Ghaderi, A., Bussu, A., Tsang, C. et al. RETRACTED ARTICLE: Effect of N-acetyl cysteine (NAC) supplementation on positive and negative syndrome scale in schizophrenia: a systematic review and meta-analysis of randomised controlled trials. Eur J Clin Pharmacol 75, 289–301 (2019). https://doi.org/10.1007/s00228-018-2595-1

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  • DOI: https://doi.org/10.1007/s00228-018-2595-1

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