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Study protocol for a randomised placebo-controlled trial of pramipexole in addition to mood stabilisers for patients with treatment resistant bipolar depression (the PAX-BD study)

Lookup NU author(s): Lumbini Azim, Paul Hindmarch, Georgiana Browne, Dr Thomas Chadwick, Emily Clare, Tony Fouweather, Nicola GoudieORCiD, Dr Eva-Maria Holstein, Phil Mawson, Dr Jenny McCafferyORCiD, Daniel Smith, Jenn Walker, Christopher Weetman, Dr Faye WolstenhulmeORCiD, Professor Allan Young, Dr Stuart Watson, Professor Hamish McAllister-WilliamsORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Background: Treatment Resistant Bipolar Depression (TRBD) is a major contributor to the burden of disease associated with Bipolar Disorder (BD). Treatment options for people experiencing bipolar depression are limited to three interventions listed by National Institute for Health and Care: lamotrigine, quetiapine and olanzapine, of which the latter two are often not well tolerated. The majority of depressed people with BD are therefore prescribed antidepressants despite limited efficacy. This demonstrates an unmet need for additional interventions. Pramipexole has been shown to improve mood symptoms in animal models of depression, in people with Parkinson’s Disease and two proof of principle trials of pramipexole for people with BD who are currently depressed. Methods: The PAX-BD study, funded by the United Kingdom (UK) National Institute for Health Research, aims to extend previous findings by assessing the efficacy, safety and health economic impact of pramipexole in addition to mood stabilisers for patients with TRBD. A randomised, double-blind, placebo controlled design is conducted in a naturalistic UK National Health Service setting. An internal pilot study to examine feasibility and acceptability of the study design is included. Participants with TRBD are screened from National Health Service secondary care services in up to 40 mental health trusts in the UK, with the aim of recruiting approximately 414 participants into a pre-randomisation phase to achieve a target of 290 randomised participants. Primary safety and efficacy measures are at 12 weeks following randomisation, with follow up of participants to 52 weeks. The primary outcome is depressive symptoms as measured by Quick Inventory for Depressive Symptomatology – Self Report. Secondary outcomes include changes in anxiety, manic symptoms, tolerability, acceptability, quality of life and costeffectiveness. Outcome measures are collected remotely using self-report tools implemented online, and observerrated assessments conducted via telephone. ANCOVA will be used to examine the difference in rating scale scores between treatment arms, and dependent on compliance in completion of weekly self-report measures. A mixed effects linear regression model may also be used to account for repeated measures.

Publication metadata

Author(s): Azim L, Hindmarch P, Browne G, Chadwick T, Clare E, Courtney P, Dixon L, Duffelen N, Fouweather T, Geddes JR, Goudie N, Harvey S, Helter T, Holstein EM, Martin G, Mawson P, McCaffery J, Morriss R, Simon J, Smith D, Stokes P, Walker J, Weetman C, Wolstenhulme F, Young AH, Watson S, McAllister-Williams H

Publication type: Article

Publication status: Published

Journal: BMC Psychiatry

Year: 2021

Volume: 21

Issue: 21

Online publication date: 05/07/2021

Acceptance date: 10/06/2021

Date deposited: 09/07/2021

ISSN (electronic): 1471-244X

Publisher: Springer Nature


DOI: 10.1186/s12888-021-03322-y


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Funder referenceFunder name
16/154/01National Institute for Health Research (NIHR)