Evidence map›Paper›PMID 28187219›Full record

SynthesisSchizophrenia bulletin2017

Kynurenic Acid in Schizophrenia: A Systematic Review and Meta-analysis.

Eric Plitman, Yusuke Iwata, Fernando Caravaggio, Shinichiro Nakajima, Jun Ku Chung, Philip Gerretsen, Julia Kim, Hiroyoshi Takeuchi, M Mallar Chakravarty, Gary Remington and 1 more

Open access · bronzeAbstract readMeta-AnalysisSystematic Review
PubMed Full text at PMC Publisher
In one paragraph

Synthesis in Schizophrenia bulletin, 2017. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 138 papers, 8 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
138citing papers in PubMed, 8 pooled it
6.7field-weighted citation impact, top 2% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

138 citing papers in PubMed, 8 syntheses or guidelines pooled it, 240 citations in OpenAlex.

  1. Pooled it
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  9. Trial
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  11. Review
  12. Article
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  14. Article
  15. Gestational kynurenine metabolites mediate effects of pregnancy adiposity on child negative affect.Journal of child psychology and psychiatry, and allied disciplines · 2026
    Article
  16. Article
  17. Article
  18. Review
  19. Article
  20. Article

78 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

11 authors at 3 institutions in 2 countries.

Eric PlitmanMultimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.
Yusuke IwataMultimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.
Fernando CaravaggioMultimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.
Shinichiro NakajimaMultimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.
Jun Ku ChungMultimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.
Philip GerretsenMultimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.
Julia KimMultimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.
Hiroyoshi TakeuchiDepartment of Psychiatry, University of Toronto, Toronto, ON, Canada.
M Mallar ChakravartyCerebral Imaging Centre, Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada.
Gary RemingtonInstitute of Medical Science, University of Toronto, Toronto, ON, Canada.
Ariel Graff-GuerreroMultimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.
Centre for Addiction and Mental Health · CAUniversity of Toronto · CAMcGill University · CA

Funding

CIHR 14196CIHR MOP-142493
6 · The paper itself

Abstract

Kynurenic acid (KYNA) is an endogenous antagonist of N-methyl-D-aspartate and α7 nicotinic acetylcholine receptors that is derived from astrocytes as part of the kynurenine pathway of tryptophan degradation. Evidence suggests that abnormal KYNA levels are involved in the pathophysiology of schizophrenia. However, this has never been assessed through a meta-analysis. A literature search was conducted through Ovid using Embase, Medline, and PsycINFO databases (last search: December 2016) with the search terms: (kynuren* or KYNA) and (schizophreni* or psychosis). English language studies measuring KYNA levels using any method in patients with schizophrenia and healthy controls (HCs) were identified. Standardized mean differences (SMDs) were calculated to determine differences in KYNA levels between groups. Subgroup analyses were separately performed for nonoverlapping participant samples, KYNA measurement techniques, and KYNA sample source. The influences of patients' age, antipsychotic status (%medicated), and sex (%male) on study SMDs were assessed through a meta-regression. Thirteen studies were deemed eligible for inclusion in the meta-analysis. In the main analysis, KYNA levels were elevated in the patient group. Subgroup analyses demonstrated that KYNA levels were increased in nonoverlapping participant samples, and centrally (cerebrospinal fluid and brain tissue) but not peripherally. Patients' age, %medicated, and %male were each positively associated with study SMDs. Overall, KYNA levels are increased in patients with schizophrenia, specifically within the central nervous system. An improved understanding of KYNA in patients with schizophrenia may contribute to the development of novel diagnostic approaches and therapeutic strategies.

Indexed as

AdultFemaleHumansKynurenic AcidMaleSchizophreniaKynurenic Acidkynurenineneuroinflammationpsychosistryptophan

Identifiers

PMID28187219
PMCPMC5472151
OpenAlexW2586728661

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.