Footnotes

• Contributors FAF (the guarantor) accepts full responsibility for the work and the conduct of the study, had access to the data and controlled the decision to publish. FAF conceived of the study, recruited participants and coordinated study visits, delivered the intervention, analysed the data, contributed to the data interpretation and drafted the manuscript. RJB conceived of the study and assisted with protocol development. GDG provided statistical advice. ND assisted with protocol development, supervised access to participants, guided data interpretation and helped draft the manuscript. NSC conceived of the study, supervised delivery of the protocol and data analysis and drafted the manuscript. All authors read and approved the final manuscript.

• Funding This study was funded by the Oakley Mental Health Research Foundation.

• Competing interests None.

• Ethics approval The NorthernXEthics Committee approved the study, and all patients provided written consent.

• Provenance and peer review Not commissioned; externally peer reviewed.