Evidence map›Paper›PMID 42142296›Full record

SynthesisCNS drugs2026

Clinical Predictors of Antidepressant Effects of Ketamine and Esketamine in Treatment-Resistant Unipolar and Bipolar Depression: A Systematic Review.

Omer A Syed, Valentyn Sobolenko, Sean M Nestor, Muhammad Ishrat Husain, Nir Lipsman, Fahad Alam, Peter Giacobbe

Abstract readSystematic Review
PubMed Publisher
In one paragraph

Synthesis in CNS drugs, 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

7 authors.

Omer A SyedInstitute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada. omer.syed@mail.utoronto.ca.ORCID http://orcid.org/0000-0002-4027-5223
Valentyn SobolenkoCentre for Addiction and Mental Health (CAMH), Toronto, ON, Canada.
Sean M NestorInstitute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
Muhammad Ishrat HusainInstitute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
Nir LipsmanInstitute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
Fahad AlamInstitute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
Peter GiacobbeInstitute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

BACKGROUND AND

objectiveKetamine and esketamine have emerged as effective and rapid-acting interventions for treatment-resistant depression. Nevertheless, the best-suited candidates for these treatments are not clear. As such, the ability to personalize treatment selection and parameters would likely improve therapeutic response. This systematic review synthesized the literature on clinical and demographic predictors of antidepressant response to ketamine and esketamine, including both unipolar and bipolar treatment-resistant depression.

methodsWe searched the databases of PubMed, Embase, Scopus, and APA PsychINFO on 25 March, 2025, with an update on 19 November, 2025, to identify studies on the clinical and demographic predictors of ketamine or esketamine effects in treatment-resistant depression. There were no restrictions on study design. Studies in a language other than English were excluded. Two authors, OAS and VS, independently reviewed studies and resolved conflicted judgments through a discussion. Risk of bias was assessed using the Cochrane RoB 2 for randomized studies and ROBINS-I for non-randomized studies. For each included study, the direction of effect (positive, negative, no association) for predictor variables was extracted.

resultsA total of 122 studies (n = 12,674) were included in the review, with 75 distinct samples (n = 6902), published between August 2006 and September 2025. There were 65 studies providing open-label ketamine, 47 secondary analyses of a trial, and 10 randomized controlled trials included. Studies most commonly treated both treatment-resistant unipolar and bipolar depression (k = 62) and solely administered intravenous ketamine at a fixed dosage of 0.5 mg/kg (k = 61). We examined the predictive value of 77 predictor variables, including body mass index, dissociation, and previous neuromodulation treatments. Most variables had more reports revealing no association with antidepressant outcomes than a positive or negative predictive ability. Some promising predictive factors, such as early response to treatment and a family history of substance use disorders, were identified and warrant further exploration.

conclusionsIn a comprehensive synthesis of predictor analyses for ketamine and esketamine treatments, most demographic and clinical variables did not confer differential outcomes to ketamine and esketamine treatments, although some promising predictive variables were identified for further investigation. CLINICAL

trial registrationPROSPERO (CRD42024554316).

Indexed as

Antidepressive AgentsBipolar DisorderDepressive Disorder, Treatment-ResistantKetamineHumansTreatment OutcomeAntidepressive AgentsEsketamineKetamine

Identifiers

PMID42142296

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.