SynthesisNeuroscience and biobehavioral reviews2018
Role of Kynurenine pathway and its metabolites in mood disorders: A systematic review and meta-analysis of clinical studies.
Synthesis in Neuroscience and biobehavioral reviews, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 81 papers, 9 of them syntheses that pooled it.
What it found
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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.
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.
Who cites it
81 citing papers in PubMed, 9 syntheses or guidelines pooled it, 119 citations in OpenAlex.
- Multimodal microglial and kynurenine pathway alterations across the affective-psychosis spectrum: a systematic review of patterns, heterogeneity, and dimensional implications.Molecular psychiatry · 2026Pooled it
- Psychopharmacological Therapy Positively Modulates Disease Activity in Inflammatory Bowel Disease: A Systematic Review.International journal of molecular sciences · 2025Pooled it
- The kynurenine pathway in major depressive disorder, bipolar disorder, and schizophrenia: a meta-analysis of 101 studies.Molecular psychiatry · 2021Pooled it
- Efficacy of onabotulinumtoxinA in the treatment of unipolar major depression: Systematic review, meta-analysis and meta-regression analyses of double-blind randomised controlled trials.Journal of psychopharmacology (Oxford, England) · 2021Pooled it
- The kynurenine pathway in bipolar disorder: a meta-analysis on the peripheral blood levels of tryptophan and related metabolites.Molecular psychiatry · 2021Pooled it
- Tryptophan Catabolites in Bipolar Disorder: A Meta-Analysis.Frontiers in immunology · 2021Pooled it
- BrainFrontiers in immunology · 2021Pooled it
- Effect of immune activation on the kynurenine pathway and depression symptoms - A systematic review and meta-analysis.Neuroscience and biobehavioral reviews · 2020Pooled it
- Effects of inflammation on the kynurenine pathway in schizophrenia - a systematic review.Journal of neuroinflammation · 2020Pooled it
- Body-weight-specific and shared metabolomic responses to acute sleep loss in young adults.Journal of translational medicine · 2026Trial
- The Usefulness of the Low-FODMAP Diet with Limited Tryptophan Intake in the Treatment of Diarrhea-Predominant Irritable Bowel Syndrome.Nutrients · 2023Trial
- Kynurenine pathway dysregulation in attention-deficit hyperactivity disorder: Impact on N-methyl-D-aspartate receptors and phasic dopamine maturation.World journal of clinical pediatrics · 2026Review
- Amino Acid-Fatty Acid Profile as a Novel Predictive Method in the Assessment of Diagnosis and Treatment Efficacy of Anxiety-Related Disorders and Mood Disorders.International journal of molecular sciences · 2026Review
- When Dryness Extends to the Brain: Brain-Related Non-Sicca Manifestations of Sjögren's Disease.Journal of clinical medicine · 2026Review
- Microbiome-Derived Short-Chain Fatty Acids and Tryptophan Metabolites in Children with Autism Spectrum Disorder: A Stool-Urine Multi-Omics Analysis.International journal of molecular sciences · 2026Article
- Gut-brain axis in health and brain disease.Chinese medical journal · 2026Review
- Contextual Regulation of the Kynurenine Pathway and Its Relevance for Personalized Psychiatry.Journal of personalized medicine · 2026Review
- Investigating targeted and untargeted approaches to biomarker discovery in fearful, adult dogs.Journal of animal science · 2026Article
- Targeting the gut-immune-brain axis: pharmacological insights from depression in inflammatory bowel disease.Frontiers in pharmacology · 2026Review
- A review of mechanisms and optimization strategies for clinical improvement after repetitive transcranial magnetic stimulation in bipolar disorder.Frontiers in psychiatry · 2026Review
21 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
6 authors at 3 institutions in 2 countries.
Funding
Abstract
Activation of the kynurenine pathway is one of the described mechanisms by which inflammation can induce depression. It involves multiple pathways including interference with the bioavailability of tryptophan central to the synthesis of the neurotransmitter serotonin. In this systematic review, we examine the relationship between kynurenine metabolites (kynurenine, kynurenic acid, tryptophan, quinolinic acid, the ratio of kynurenine and tryptophan) and mood disorders by conducting a meta-analysis. Fifty-six studies were identified, 21 met inclusion criteria and 14 were deemed suitable (9 investigating unipolar depression and 5 bipolar disorder). We found decreased levels of kynurenine in unipolar major depression vs. healthy controls but studies were significantly heterogeneous in nature. No significant differences were found in tryptophan levels or kynurenine/tryptophan ratios. Kynurenine metabolites are likely to play a role in major depression but an exact etiological role in mood disorder seem complex and requires further research.
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Registered trials
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.