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Cochrane Database of Systematic Reviews

Antioxidant treatments for schizophrenia

Overview of attention for article published in Cochrane database of systematic reviews, February 2016
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About this Attention Score

  • In the top 25% of all research outputs scored by Altmetric
  • High Attention Score compared to outputs of the same age (90th percentile)
  • Above-average Attention Score compared to outputs of the same age and source (63rd percentile)

Mentioned by

24 tweeters
3 Facebook pages
1 Google+ user


60 Dimensions

Readers on

244 Mendeley
1 CiteULike
Antioxidant treatments for schizophrenia
Published in
Cochrane database of systematic reviews, February 2016
DOI 10.1002/14651858.cd008919.pub2
Pubmed ID

Pedro V S Magalhães, Olivia Dean, Ana C Andreazza, Michael Berk, Flávio Kapczinski


There is accumulating evidence that progressive changes in brain structure and function take place as schizophrenia unfolds. Among many possible candidates, oxidative stress may be one of the mediators of neuroprogression, grey matter loss and subsequent cognitive and functional impairment. Antioxidants are exogenous or endogenous molecules that mitigate any form of oxidative stress or its consequences. They may act from directly scavenging free radicals to increasing anti-oxidative defences. There is evidence that current treatments impact oxidative pathways and may to some extent reverse pro-oxidative states in schizophrenia. The existing literature, however, indicates that these treatments do not fully restore the deficits in antioxidant levels or restore levels of oxidants in schizophrenia. As such, there has been interest in developing interventions aimed at restoring this oxidative balance beyond the benefits of antipsychotics in this direction. If antioxidants are to have a place in the treatment of this serious condition, the relevant and up-to-date information should be available to clinicians and investigators. To evaluate the effect of antioxidants as add-on treatments to standard antipsychotic medication for improving acute psychotic episodes and core symptoms, and preventing relapse in people with schizophrenia. We searched the Cochrane Schizophrenia Group's Study-Based Register of Trials which is based on regular searches of CINAHL, BIOSIS, AMED, Embase, PubMed, MEDLINE, PsycINFO, and registries of clinical trials. There are no language, time, document type, or publication status limitations for inclusion of records in the register. We ran this search in November 2010, and again on 8 January 2015. We also inspected references of all identified studies for further trials and contacted authors of trials for additional information. We included reports if they were randomised controlled trials (RCTs) involving people with schizophrenia who had been allocated to either a substance with antioxidant potential or to a placebo as an adjunct to standard antipsychotic treatment. We independently extracted data from these trials and we estimated risk ratios (RR) or mean differences (MD), with 95% confidence intervals (CI). We assessed risk of bias for included studies and created a 'Summary of findings' table using GRADE. The review includes 22 RCTs of varying quality and sample size studying Ginkgo biloba, N-acetyl cysteine (NAC), allopurinol, dehydroepiandrosterone (DHEA), vitamin C, vitamin E or selegiline. Median follow-up was eight weeks. Only three studies including a minority of the participants reported our a priori selected primary outcome of clinically important response. Short-term data for this outcome (measured as at least 20% improvement in scores on Positive and Negative Syndrome Scale (PANSS)) were similar (3 RCTs, n = 229, RR 0.77, 95% CI 0.53 to 1.12, low quality evidence). Studies usually reported only endpoint psychopathology rating scale scores. Psychotic symptoms were lower in those using an adjunctive antioxidant according to the PANSS ( 7 RCTS, n = 584, MD -6.00, 95% CI -10.35 to -1.65, very low quality evidence) and the Brief Psychiatric Rating Scale (BPRS) (8 RCTS, n = 843, MD -3.20, 95% CI -5.63 to -0.78, low quality evidence). There was no overall short-term difference in leaving the study early (16 RCTs, n = 1584, RR 0.73, 95% CI 0.48 to 1.11, moderate quality evidence), or in general functioning (2 RCTs, n = 52, MD -1.11, 95% CI -8.07 to 5.86, low quality evidence). Adverse events were generally poorly reported. Three studies reported useable data for 'any serious adverse effect', results were equivocal (3 RCTs, n = 234, RR 0.65, 95% CI 0.19 to 2.27, low quality evidence). No evidence was available for relapse, quality of life or service use. Although 22 trials could be included in this review, the evidence provided is limited and mostly not relevant to clinicians or consumers. Overall, although there was low risk of attrition and selective data reporting bias within the trials, the trials themselves were not adequately powered and need more substantial follow-up periods. There is a need for larger trials with longer periods of follow-up to be conducted. Outcomes should be meaningful for those with schizophrenia, and include measures of improvement and relapse (not just rating scale scores), functioning and quality of life and acceptability and, importantly, safety data.

Twitter Demographics

The data shown below were collected from the profiles of 24 tweeters who shared this research output. Click here to find out more about how the information was compiled.

Mendeley readers

The data shown below were compiled from readership statistics for 244 Mendeley readers of this research output. Click here to see the associated Mendeley record.

Geographical breakdown

Country Count As %
United Kingdom 1 <1%
Spain 1 <1%
Unknown 242 99%

Demographic breakdown

Readers by professional status Count As %
Student > Master 49 20%
Student > Bachelor 35 14%
Researcher 21 9%
Student > Ph. D. Student 20 8%
Student > Doctoral Student 14 6%
Other 48 20%
Unknown 57 23%
Readers by discipline Count As %
Medicine and Dentistry 65 27%
Psychology 32 13%
Nursing and Health Professions 17 7%
Neuroscience 15 6%
Biochemistry, Genetics and Molecular Biology 11 5%
Other 40 16%
Unknown 64 26%

Attention Score in Context

This research output has an Altmetric Attention Score of 16. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 25 September 2021.
All research outputs
of 20,568,640 outputs
Outputs from Cochrane database of systematic reviews
of 12,078 outputs
Outputs of similar age
of 368,807 outputs
Outputs of similar age from Cochrane database of systematic reviews
of 191 outputs
Altmetric has tracked 20,568,640 research outputs across all sources so far. Compared to these this one has done particularly well and is in the 91st percentile: it's in the top 10% of all research outputs ever tracked by Altmetric.
So far Altmetric has tracked 12,078 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 28.3. This one has gotten more attention than average, scoring higher than 67% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 368,807 tracked outputs that were published within six weeks on either side of this one in any source. This one has done particularly well, scoring higher than 90% of its contemporaries.
We're also able to compare this research output to 191 others from the same source and published within six weeks on either side of this one. This one has gotten more attention than average, scoring higher than 63% of its contemporaries.