Evidence map›Paper›PMID 42717383›Full record

ArticleTrials2026

PrEgabalin for Treatment Resistant generalised Anxiety disorder (PETRA): study protocol for a double-blind randomised controlled trial set in the UK.

Larisa Duffy, Carolyn A Chew-Graham, Brian C F Ching, Beverley Chipp, Charlotte Clarke, Liz Deane, Hakim-Moulay Dehbi, Nicholas Freemantle, Rafael Gafoor, Lauren Harding-Brown and 12 more

Abstract readClinical Trial Protocol
PubMed Full text at PMC Publisher
In one paragraph

Article in Trials, 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

22 authors.

Larisa DuffyDivision of Psychiatry, University College London, London, UK. larisa.duffy@ucl.ac.uk.ORCID https://orcid.org/0000-0002-0093-3877
Carolyn A Chew-GrahamSchool of Medicine, Keele University, Staffordshire, UK.
Brian C F ChingDivision of Psychiatry, University College London, London, UK.
Beverley ChippDivision of Psychiatry, University College London, London, UK.
Charlotte ClarkeComprehensive Clinical Trial Unit, University College London, London, UK.
Liz DeaneComprehensive Clinical Trial Unit, University College London, London, UK.
Hakim-Moulay DehbiComprehensive Clinical Trial Unit, University College London, London, UK.
Nicholas FreemantleComprehensive Clinical Trial Unit, University College London, London, UK.
Rafael GafoorComprehensive Clinical Trial Unit, University College London, London, UK.
Lauren Harding-BrownDivision of Psychiatry, University College London, London, UK.
Rachael HunterCentre for Applied Health Research, University College London, London, UK.
Berry JudeDivision of Psychiatry, University College London, London, UK.
David KesslerPopulation Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK.
David LewisVauxhall Primary Health Care, Liverpool, UK.
Gemma LewisDivision of Psychiatry, University College London, London, UK.
Louise MarstonDepartment of Primary Care and Population Health, University College London, London, UK.
Oliver J RobinsonInstitute of Cognitive Neuroscience, University College London, London, UK.
Jonathan P RoiserInstitute of Cognitive Neuroscience, University College London, London, UK.
David TaylorPharmacy Department, South London and Maudsley NHS Foundation Trust, London, UK.
Kate WaltersDepartment of Primary Care and Population Health, University College London, London, UK.
Nicola WilesPopulation Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK.
Glyn LewisDivision of Psychiatry, University College London, London, UK.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundGeneralised anxiety disorder (GAD) is common and increasingly recognised in primary care. Although antidepressants and psychological therapies are first-line treatments, many patients have residual anxiety and limited access to therapy. Evidence for effective next-step pharmacological options for treatment resistant anxiety remains limited. This paper describes the protocol for the PETRA trial, which will evaluate the clinical and cost-effectiveness of adding pregabalin to antidepressant treatment, compared with placebo, for people with GAD who have not responded or partially responded to antidepressant treatment.

methodsPETRA is a multicentre, individually randomised, double-blind, placebo-controlled superiority trial conducted in UK primary care. Participants are recruited by the study team from approximately 150 General Practices and randomised in a 1:1 ratio, using minimisation, to either pregabalin or a matching placebo for 26 weeks (followed by a tapering period where their dosage is reduced over approximately 4 weeks). Sample size is 498. Eligible participants are adults aged 18-74 years, who have been taking antidepressant medication for at least 8 weeks, received treatment with at least one other antidepressant before their current antidepressant and meet ICD-11 criteria for GAD and score ≥ 12 on the revised clinical interview schedule (CIS-R) total score. Follow-up assessments are at 3, 6, 12, 26 and ~ 30 weeks. Our primary outcome measure will be anxiety symptoms measured with GAD-7 at 12 weeks (continuous score). Secondary outcomes are anxiety (GAD-7) at other time points, depressive and panic symptoms, suicidal thoughts, self-rated global improvement, adherence to study medication, serious adverse events, adverse effects, alcohol consumption and benzodiazepine use, quality of life and resources and costs used. The ~ 30-week assessment will investigate symptoms during the withdrawal from pregabalin. Exploratory analyses will include cognitive tasks. A cost-effectiveness analysis and a nested qualitative study will evaluate the implementation and intervention acceptability. DISCUSSION: The trial findings will inform primary care prescribing practice by providing an accurate and generalisable estimate of the clinical and cost-effectiveness of prescribing pregabalin to individuals with generalised anxiety who have not responded or only partially responded to antidepressant treatment.

trial registrationControlled Trials ISRCTN Registry, ISRCTN 16993990, registered on 19/09/2023. First participant enrolled in January 2024.

Indexed as

Anti-Anxiety AgentsAntidepressive AgentsGeneralized Anxiety DisorderPregabalinAdolescentAdultAgedCost-Benefit AnalysisDouble-Blind MethodDrug CostsDrug ResistanceDrug Therapy, CombinationEquivalence Trials as TopicFemaleHumansMaleAnti-Anxiety AgentsAntidepressive AgentsPregabalinAnxietyGADPregabalinPrimary careRCTTreatment-resistant anxiety

Identifiers

PMID42717383
PMCPMC13555984

What OpenQuestion holds

Textmetadata
Read underepoch 390

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.