Evidence map›Paper›PMID 42393817›Full record

ArticleBJPsych open2026

Sustained mood improvement with laughing gas exposure (SMILE): a randomised, placebo-controlled pilot trial of nitrous oxide for treatment-resistant depression: commentary, Kalmar et al.

Alain F Kalmar, Pascal Sienaert, Filip Bouckaert, Steffen Rex

Abstract read
In one paragraph

Article in BJPsych open, 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

4 authors.

Alain F KalmarElectronics and Information Systems, https://ror.org/00cv9y106Ghent University Faculty of Engineering and Architecture, Belgium.ORCID https://orcid.org/0000-0003-2036-9019
Pascal SienaertDepartment of Mood Disorders, University Psychiatric Centre KU Leuven, Belgium.
Filip BouckaertOld Age Psychiatry, University Psychiatric Centre KU Leuven, Belgium.
Steffen RexAnaesthesiology, University Hospitals Leuven, Belgium.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Nitrous oxide is being investigated as a treatment for therapy-resistant depression, yet its environmental implications as a potent greenhouse gas are largely unaddressed. A single 1 h treatment generates ∼150 kg CO

Indexed as

climate changeN2ONitrous oxidesustainabilitytreatment-resistant depression

Identifiers

PMID42393817
PMCPMC13359053

What OpenQuestion holds

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LicenceCC BY
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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.