Evidence map›Paper›PMID 42548890›Full record

SynthesisFrontiers in psychiatry2026

(Es)ketamine in functional neurological disorder: a systematic review.

Bruce Tamilson, Michael Chitolie, Jan Coebergh, Niruj Agrawal, Norman Poole, Matt Butler, Richard Kanaan, Timothy Nicholson

Abstract readSystematic Review
In one paragraph

Synthesis in Frontiers in psychiatry, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
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

0 citing papers in PubMed.

No citing paper in PubMed yet.

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

8 authors.

Bruce TamilsonNeuropsychiatry Service, South West London & St George's Mental Health NHS Trust, St George's Hospital, London, United Kingdom.
Michael ChitolieDepartment of Liaison Psychiatry, Kingston Hospital, London, United Kingdom.
Jan CoeberghDivision of Psychiatry, University College of London, London, United Kingdom.
Niruj AgrawalNeuropsychiatry Service, South West London & St George's Mental Health NHS Trust, St George's Hospital, London, United Kingdom.
Norman PooleInstitute of Psychiatry, Psychology, and Neuroscience, King's College London, London, United Kingdom.
Matt ButlerInstitute of Psychiatry, Psychology, and Neuroscience, King's College London, London, United Kingdom.
Richard KanaanDepartment of Psychiatry, University of Melbourne, Melbourne, VIC, Australia.
Timothy NicholsonInstitute of Psychiatry, Psychology, and Neuroscience, King's College London, London, United Kingdom.

Funding

Wellcome Trust
6 · The paper itself

Abstract

Background and aim: Functional neurological disorder (FND) is a common and disabling condition for which effective treatments remain limited. Clinical outcomes are often variable, particularly in chronic and comorbid presentations. Ketamine and esketamine are increasingly used across a range of neuropsychiatric conditions. This review aimed to synthesise the existing evidence regarding their use in FND. Methods: A systematic review of PubMed, PsycINFO and Google Scholar was conducted up to December 2025. Studies reporting clinical outcomes following (Es)ketamine administration in functional neurological symptoms were included. Owing to substantial clinical and methodological heterogeneity, findings were synthesised narratively. Results: Thirteen studies were identified, predominantly comprising case reports and small case series. Across the included studies, some patients were reported to experience improvement in functional motor symptoms, functional dissociative seizures, and other functional presentations following ketamine or esketamine administration. Interpretation of these findings is limited by the uncontrolled nature of the evidence base, heterogeneity of diagnoses and outcomes, and the potential influence of publication and expectancy bias. Adverse effects were variably reported and were generally described as transient in supervised clinical settings. Conclusion: The current evidence base is limited to predominantly uncontrolled and highly heterogeneous studies and is insufficient to establish the efficacy of (Es)ketamine for FND. Although improvements in functional symptoms have been reported across several FND presentations, it remains unclear whether these reflect direct effects on functional symptoms, indirect benefits arising from psychiatric improvement, or other non-specific therapeutic factors. While no firm conclusions regarding efficacy can be drawn, the existing data suggest that further investigation is justified, and prospective controlled trials are needed to clarify the potential role of (Es)ketamine in FND.

Indexed as

conversion disorderEsketaminefunctional/dissociative seizuresfunctional neurological disorder (FND)ketamine

Identifiers

PMID42548890
PMCPMC13430003

What OpenQuestion holds

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Registered trials

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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.