Evidence map›Paper›PMID 34180293›Full record

SynthesisJournal of psychopharmacology (Oxford, England)2021

Ketamine's effect on inflammation and kynurenine pathway in depression: A systematic review.

Emma Kopra, Valeria Mondelli, Carmine Pariante, Naghmeh Nikkheslat

Registry-linked trialOpen access · hybridAbstract readSystematic Review
In one paragraph

Synthesis in Journal of psychopharmacology (Oxford, England), 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT06821087 (Evaluating the Neuromodulatory Effect of Ketamine in Long COVID), which is not on this map. Cited by 48 papers, 2 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
48citing papers in PubMed, 2 pooled it
3.8field-weighted citation impact, top 5% 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.

NCT06821087 phase2completednot on this mapstarted 2025, after this paper: background citation

Evaluating the Neuromodulatory Effect of Ketamine in Long COVID: A Pilot Study Targeting Fatigue and Neurocognitive Symptoms

TypeinterventionalSponsorUniversity of Texas at AustinRan2025 to 2026Enrolled20ConditionsLong COVIDArmsKetamine only
3 · Its place in the literature

Who cites it

48 citing papers in PubMed, 2 syntheses or guidelines pooled it, 78 citations in OpenAlex.

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  10. Inflammation and treatment strategies for suicidal behavior.The world journal of biological psychiatry : the official journal of the World Federation of Societies of Biological Psychiatry · 2026
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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

4 authors at 1 institution in 1 country.

Emma KopraDepartment of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK.ORCID https://orcid.org/0000-0003-4447-5393
Valeria MondelliDepartment of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK.
Carmine ParianteDepartment of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK.
Naghmeh NikkheslatDepartment of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK.
King's College London · GB

Funding

Wellcome Trust
6 · The paper itself

Abstract

backgroundKetamine is a novel rapid-acting antidepressant with high efficacy in treatment-resistant patients. Its exact therapeutic mechanisms of action are unclear; however, in recent years its anti-inflammatory properties and subsequent downstream effects on tryptophan (TRP) metabolism have sparked research interest.

aimThis systematic review examined the effect of ketamine on inflammatory markers and TRP-kynurenine (KYN) pathway metabolites in patients with unipolar and bipolar depression and in animal models of depression.

methodsMEDLINE, Embase, and PsycINFO databases were searched on October 2020 (1806 to 2020).

resultsOut of 807 initial results, nine human studies and 22 animal studies on rodents met the inclusion criteria. Rodent studies provided strong support for ketamine-induced decreases in pro-inflammatory cytokines, namely in interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α and indicated anti-inflammatory effects on TRP metabolism, including decreases in the enzyme indoleamine 2,3-dioxygenase (IDO). Clinical evidence was less robust with high heterogeneity between sample characteristics, but most experiments demonstrated decreases in peripheral inflammation including in IL-1β, IL-6, and TNF-α. Preliminary support was also found for reduced activation of the neurotoxic arm of the KYN pathway.

conclusionKetamine appears to induce anti-inflammatory effects in at least a proportion of depressed patients. Suggestions for future research include investigation of markers in the central nervous system and examination of clinical relevance of inflammatory changes.

Indexed as

AnimalsAntidepressive AgentsAnti-Inflammatory AgentsBipolar DisorderCytokinesHumansInflammationKetamineKynurenineMajor Depressive DisorderTryptophanAntidepressive AgentsAnti-Inflammatory AgentsCytokinesKetamineKynurenineTryptophancytokinedepressioninflammationKetaminekynurenine

Identifiers

PMID34180293
PMCPMC8358579
OpenAlexW3174390234

What Socratic holds

Textmetadata
LicenceCC BY
Read underepoch 390

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 Socratic graph.