CRediT contribution statement
Debbie Tallon (https://orcid.org/0000-0001-9195-5010): Conceptualisation, Data curation, Formal analysis, Investigation, Methodology, Project administration, Supervision, Validation, Writing – original draft, Writing – reviewing and editing.
Laura Thomas (https://orcid.org/0000-0002-8514-2045): Investigation, Methodology, Project administration, Writing – reviewing and editing.
Sally Brabyn (https://orcid.org/0000-0001-5381-003X): Investigation, Project administration, Writing – reviewing and editing.
Brian CF Ching (https://orcid.org/0000-0002-2179-9793): Investigation, Project administration, Writing – reviewing and editing.
Fiona Fox (https://orcid.org/0000-0001-7313-8105): Data curation, Formal analysis, Investigation, Methodology, Project administration, Validation, Writing – original draft, Writing – reviewing and editing.
Jane Sungmin Hahn (https://orcid.org/0000-0002-4584-9441): Investigation, Project administration, Writing – reviewing and editing.
Berry Jude (https://orcid.org/0009-0001-8612-0630): Investigation, Project administration, Writing – reviewing and editing.
Jinshuo Li (https://orcid.org/0000-0003-1496-7450): Conceptualisation, Data curation, Formal analysis, Investigation, Methodology, Project administration, Validation, Writing – original draft, Writing – reviewing and editing.
José A López-López (https://orcid.org/0000-0002-9655-3616): Conceptualisation, Data curation, Formal analysis, Investigation, Methodology, Project administration, Validation, Writing – original draft, Writing – reviewing and editing.
Katarzyna Stawarz (https://orcid.org/0000-0001-9021-0615): Conceptualisation, Data curation, Formal analysis, Investigation, Methodology, Project administration, Software, Validation, Writing – original draft, Writing – reviewing and editing.
Abigail Taylor (https://orcid.org/0000-0001-9013-1378): Formal analysis, Investigation, Project administration, Writing – reviewing and editing.
Qi Wu (https://orcid.org/0000-0002-8281-7799): Conceptualisation, Data curation, Formal analysis, Methodology, Project administration, Validation, Writing – original draft, Writing – reviewing and editing.
Mekeda X Logan (https://orcid.org/0000-0001-7899-7531): Investigation, Project administration, Writing – reviewing and editing.
Alex Burrage (https://orcid.org/0009-0000-9300-995X): Conceptualisation, Project administration, Supervision, Writing – reviewing and editing.
Deborah M Caldwell (https://orcid.org/0000-0001-8014-7480): Conceptualisation, Formal analysis, Investigation, Methodology, Project administration, Supervision, Writing – reviewing and editing.
David Coyle (https://orcid.org/0000-0002-5103-0379): Conceptualisation, Funding acquisition, Methodology, Project administration, Software, Supervision, Writing – reviewing and editing.
Simon Gilbody (https://orcid.org/0000-0002-8236-6983): Conceptualisation, Funding acquisition, Methodology, Project administration, Supervision, Writing – reviewing and editing.
Paul Lanham: Conceptualisation, Funding acquisition, Writing – reviewing and editing.Glyn Lewis (https://orcid.org/0000-0001-5205-8245): Conceptualisation, Funding acquisition, Methodology, Project administration, Supervision, Writing – reviewing and editing.
Stephanie MacNeill (https://orcid.org/0000-0001-6553-1433): Formal analysis, Methodology, Project administration, Validation, Writing – original draft, Writing – reviewing and editing.
Irwin Nazareth (https://orcid.org/0000-0003-2146-9628): Conceptualisation, Funding acquisition, Methodology, Writing – reviewing and editing.
Steve Parrott (https://orcid.org/0000-0002-0165-1150): Conceptualisation, Funding acquisition, Methodology, Project administration, Supervision, Writing – reviewing and editing.
Tim J Peters (https://orcid.org/0000-0003-2881-4180): Conceptualisation, Formal analysis, Funding acquisition, Methodology, Project administration, Supervision, Writing – reviewing and editing.
Chris Preist (https://orcid.org/0000-0002-5094-5294): Conceptualisation, Methodology, Project administration, Software, Supervision, Writing – reviewing and editing.
Roz Shafran (https://orcid.org/0000-0003-2729-4961): Conceptualisation, Funding acquisition, Methodology, Project administration, Supervision, Writing – reviewing and editing.
Katrina Turner (https://orcid.org/0000-0002-6375-2918): Conceptualisation, Formal analysis, Funding acquisition, Investigation, Methodology, Project administration, Supervision, Validation, Writing – original draft, Writing – reviewing and editing.
Nicky J Welton (https://orcid.org/0000-0003-2198-3205): Conceptualisation, Formal analysis, Funding acquisition, Methodology, Project administration, Supervision, Writing – reviewing and editing.
Chris Williams (https://orcid.org/0000-0001-5387-2863): Conceptualisation, Funding acquisition, Methodology, Project administration, Supervision, Writing – reviewing and editing.
David Kessler (https://orcid.org/0000-0001-5333-132X): Conceptualisation, Formal analysis, Funding acquisition, Methodology, Project administration, Supervision, Writing – original draft, Writing – reviewing and editing.
Nicola Wiles (https://orcid.org/0000-0002-5250-3553): Conceptualisation, Formal analysis, Funding acquisition, Methodology, Project administration, Supervision, Writing – original draft, Writing – reviewing and editing.
Rachel Churchill: Conceptualisation, Funding acquisition.
Una Macleod: Conceptualisation, Funding acquisition.
Catherine Wevill: Conceptualisation, Funding acquisition.
Mike Jones: Software.
Kieren Pitts: Software.
Tessa Alexander: Software.
Josh Jones: Software.
David James: Software.
Other contributions
Paul Lanham: PPI representative.
Acknowledgements
The authors would like to thank the patients, therapists and supervisors who have participated this research, and the collaborating GP practices who supported the pilot study and RCT. We are also grateful to the NIHR Clinical Research Network who supported participant recruitment activities for several aspects of the programme. We would also like to thank the people with lived experience who contributed to the development of the INTERACT intervention and advised on other aspects of the programme.
The INTERACT Programme Steering Group (PSG) [who also acted as the Trial Steering Committee (TSC) for the main RCT] and Data Monitoring Committee (DMC) have provided invaluable support and guidance throughout the programme. The PSC was chaired by André Tylee (until July 2021), Sandra Eldridge (July–October 2021) and Ed Watkins (from October 2021), and included Shaun Lawson, Philip Pallmann (from November 2021), Michael Moore (from May 2021), Mark Tucker, Vivien Lindow (until January 2021), and Marta Sawinska (from April 2021). DMC members were: David Kingdon (Chair), Chris Burton and Nikki Totton.
We are grateful to our research programme administrators, Vivien Jones and Fiona Reid.
We would also like to acknowledge the support of Kieren Pitts, Mike Jones, Tessa Alexander and Josh Jones who developed and maintained the INTERACT CBT platform on behalf of University of Bristol Research IT.
We thank Richard Moore and Anne Garland, Matthew Whalley (Psychology Tools), Carol Vivyan (GetSelfHelp), Centre for Clinical Interventions, and Five Areas Ltd. for kindly granting permission for their CBT resources to be used within the INTERACT platform.
We are grateful to Rachel Churchill, Una Macleod and Catherine Wevill who originally contributed to securing funding for the programme of work. We also thank Paul Roy (BNSSG Integrated Care Board) and Anna Brooke (University of Bristol, Division of Research, Enterprise and Innovation) who have provided helpful advice and support throughout the programme.
This study was designed and delivered in collaboration with the Bristol Trials Centre, a UKCRC-registered clinical trials unit. This study was also supported by the National Institute for Health and Care Research Bristol Biomedical Research Centre. Supplementary funding was provided by the NIHR School for Primary Care Research (SPCR - 2014-10043 Award: L).
Study data were collected and managed using REDCap73 hosted at the University of Bristol.
All research at Great Ormond Street Hospital NHS Foundation Trust and UCL Great Ormond Street Institute of Child Health is made possible by the NIHR Great Ormond Street Hospital Biomedical Research Centre.
Data-sharing statement
We encourage and will facilitate data-sharing with ‘bona fide’ researchers. In the first instance, all data requests should be submitted to the coleads, Nicola Wiles and David Kessler, for consideration. Access to anonymised data may be granted following review.
Data from the INTERACT RCT (underpinning the clinical and cost-effectiveness analyses) will be made available as a controlled data set managed by the University of Bristol’s Research Data Repository (https://data.bris.ac.uk/data). To gain access, data requestors will need to apply for access at www.bristol.ac.uk/staff/researchers/data/accessing-research-data/. Data release will be contingent on a signed data access agreement. This agreement limits use of data to non-commercial research only. Requests for any other purposes must be negotiated separately.
Ethics statement
Informing the development of online CBT Materials for an integrated approach to delivering CBT (INTERACT therapist survey and Delphi study)
Approved by the Faculty of Health Sciences Research Ethics Committee (FREC reference: 31642) at the University of Bristol (29/2/16) and the HRA (8/3/16), (IRAS ID: 198271).
Designing and developing integrated therapist and online CBT for depression (INTERACT phase 1)
Approved by the South West – Frenchay NHS Research Ethics Committee (REC) (24/3/17) and HRA (3/4/17), (IRAS ID: 221433; REC reference: 17/SW/0058).
The pilot evaluation of an online platform for delivering integrated high-intensity cognitive–behavioural therapy for depression (INTERACT phase 2)
Approved by the South West – Central Bristol NHS Research Ethics Committee (15/11/17) and HRA (17/11/17), (IRAS ID: 235168; REC reference: 17/SW/0243).
Multicentre randomised controlled trial of integrated therapist and online CBT for depression in primary care (INTERACT RCT)
The RCT (including the nested qualitative and cost-effectiveness studies) was approved by the South West – Frenchay Research Ethics Committee (20/3/19), (REC reference 19/SW/0038, IRAS ID: 257620) and HRA (15/5/19).
Information governance statement
The University of Bristol is committed to handling all personal information in line with the UK Data Protection Act (2018) and the General Data Protection Regulation (EU GDPR) 2016/679. Under the Data Protection legislation, the University of Bristol is the Data Controller, and you can find out more about how we handle personal data, including how to exercise your individual rights, and the contact details for our Data Protection Officer here: www.bristol.ac.uk/secretary/data-protection/gdpr/data-protection-officer/.
Disclosure of interests
Full disclosure of interests: Completed ICMJE forms for all authors, including all related interests, are available in the toolkit on the NIHR Journals Library report publication page at https://doi.org/10.3310/GJNW3912.
Primary conflicts of interest: Debbie Tallon, Laura Thomas, Sally Brabyn, Jinshuo Li: salaries funded by INTERACT NIHR PGfAR grant (RP-PG-0514-20012) to institution.
Deborah M Caldwell: Committee member of NIHR HTA Prioritisation Committee – Social Care – 1/5/24 – 31/5/27 (non-financial interest).
Simon Gilbody: HTA Post-Funding Committee teleconference (2017–20), HTA Funding Committee Policy Group (2017–22), HTA Commissioning Committee (2016–20).
Paul Lanham: payment and travel costs for attending INTERACT meetings.
Glyn Lewis: NIHR grant to institution. NIHR, Wellcome Trust grants. Travel and accommodation to attend ECNP 2023 (personal payment). Chair of STOP-D trial TSC (no payment).
José A López-López: NIHR funding for 6 months in 2017 to carry out the statistical analyses for the INTERACT systematic review and NMA. The funder had no further role in the conduct of the analyses nor in the interpretation and reporting of results. Spanish Ministry of Science and Innovation (2020–4) and Fundación Séneca (Region of Murcia, 2023–5): awarded two principal investigator grants from these public funders based in Spain to carry out research on methods for meta-analysis (unrelated to INTERACT). Instructional Research Group (2024): consulting fees for 8 hours’ work on a meta-analysis project unrelated to INTERACT. Spanish Association of Physiotherapists (2024): payment for a 12-hour course on NMA (unrelated to INTERACT).
Stephanie MacNeill: HTA General Committee – 11 August 2020 (ongoing).
Irwin Nazareth: receipt of research grant awards from NIHR, UKRI and Wellcome Trust. PRIMENT CTU funded by NIHR 2021. Paid for attending grant panel meetings in London Barts Charity and Eire for HRB panel meetings. Chair of the Drug Safety Monitoring committee for the APRIL RCT led by the LSHTM. On the advisory board of the CRUK core funded CTU at QMUL.
Steve Parrott: NIHR i4i: RESTART-PD grant NIHR206530; NIHR GHR (RIGHT): SCIMITAR–SA Trial grant NIHR205601; NIHR HTA: PORTRAIT grant NIHR159676; NIHR HTA: HAMLET grant NIHR157343; YORQUIT grant from Yorkshire Cancer Research (YCR); NIHR PHR Advance D trial grant NIHR154546; NIHR HTA: (SCOOTT) trial grant NIHR154694; Police drug diversion grant from Cabinet Office; TB-Diabetes grant from the Higher Education Commission NIHR RfPB: (PAMHOP) grant NIHR203484; NIHR PHR: (SCeTCH) grant NIHR132158.
Tim J Peters: NIHR PGfAR grant.
Roz Shafran: NIHR PGfAR (RP-PG-0514-20012) grant to institution as coinvestigator. HTA Prioritisation Committee A 2017–21, HTA Prioritisation Committee C 2017–20.
Katrina Turner: NIHR PGfAR grant to institution (grant co-applicant). HTA Commissioning Committee 2017–22.
Nicky J Welton: NIHR grant to institution.
Chris Williams: Five Areas Ltd (employed), and for which, CW is Director and shareholder, has provided licence agreement to use materials in the INTERACT platform. Payments made to Five Areas Ltd for Chris Williams’s time on INTERACT project. Other grants/contracts via Five Areas Ltd (research, CBT resources, training contracts – multiple). Five Areas Limited markets the worksheets and related training materials and receives licence fees. Research grants University of Aberdeen, University of Helsinki and more. Five Areas Ltd: Royalty for sales of the worksheets and related resources (books/classes, online resources) in Canada via the Canadian Mental Health Association. Royal College of Psychiatrists: workshops × 2 annually. NHS Greater Glasgow and Clyde: eating disorders teaching session annually. University of Exeter Nurture U. DMEC Chair; University of Manchester EQUITy PSC Chair; University of Central Lancashire COMMITS TSC Chair (all personal capacity/University of Glasgow). Adviser Anxiety UK: personal capacity/University of Glasgow. Stock options: Five Areas Ltd (trading company), Five Areas Resources Ltd (holding company).
David Kessler: NIHR PGfAR (RP-PG-0514-20012) colead on grant to University of Bristol. NIHR HTA grants for PETRA trial (NIHR134074) and aripiprazole/sertraline combination trial (NIHR132773), Wellcome Trust RELMED study grant (UNS141767) Chair of PSC for REDUCE (NIHR PGfAR) (no payment). Honorarium for RCGP lecture on Bipolar disorder December 2023.
Nicola Wiles: NIHR PGfAR (RP-PG-0514-20012) colead on grant to University of Bristol. NIHR HTA (NIHR134074; NIHR127337; NIHR132343), Wellcome Trust, MRC, NIHR SPCR grants to University of Bristol. Chair of Community Navigator Trial DMEC (no payment), Member StratCare Trial DMEC (no payment), Member VIP Trial (no payment).
Brian CF Ching, Fiona Fox, Jane Sungmin Hahn, Berry Jude, Mekeda X Logan, Chris Preist, Katarzyna Stawarz, Abigail Taylor, Qi Wu, Alex Burrage, David Coyle: none declared.
Copyright and credit statement
Every effort has been made to obtain the necessary permissions for reproduction, to credit original sources appropriately and to respect copyright requirements. However, despite our diligence, we acknowledge the possibility of unintentional omissions or errors, and we welcome notifications of any concerns regarding copyright or permissions.
Publications
Work package 1: intervention development
Davies SR, Caldwell DM, López-López JA, Dawson S, Wiles N, Kessler D, et al. The process and delivery of cognitive behavioural therapy (CBT) for depression in adults: a network meta‐analysis. Cochrane Database Syst Rev 2018;10:CD013140. https://doi.org/10.1002/14651858.CD013140
Davies SR, Caldwell DM, Dawson S, Sampson SJ, Welton NJ, Wiles N, et al. Multimedia‐delivered cognitive behavioural therapy versus face‐to‐face cognitive behavioural therapy for depression in adults. Cochrane Database Syst Rev 2018;11:CD013184. https://doi.org/10.1002/14651858.CD013184
Stawarz K, Preist C, Tallon D, Wiles N, Coyle D. User Experience of CBT Apps for depression: an analysis of app functionality and user reviews. J Med Internet Res 2018;20:e10120. www.jmir.org/2018/6/e10120/
López-López JA, Davies SR, Caldwell DM, Churchill R, Peters TJ, Tallon D, et al. The process and delivery of CBT for depression in adults: a systematic review and network meta-analysis. Psychol Med 2019;49:1937–47. https://doi.org/10.1017/S003329171900120X
Stawarz K, Preist C, Coyle D. Use of smartphone apps, social media and online resources to support mental health and wellbeing: an online survey. JMIR Ment Health 2019;6:e12546. https://mental.jmir.org/2019/7/e12546/
Tallon D, McClay CA, Kessler D, Lewis G, Peters TJ, Shafran R, et al. Materials used to support cognitive behavioural therapy for depression: a survey of therapists’ clinical practice and views. Cogn Behav Ther 2019;48:463–81. https://doi.org/10.1080/16506073.2018.1541927
Author accepted manuscript available at: https://research-information.bris.ac.uk/ws/portalfiles/portal/173757515/Submitted_manuscript_proof_23_10_2018.pdf
Materials used to support cognitive behavioural therapy for depression: a survey of therapists’ clinical practice and views. CBT Today, May 2019. Short summary of results published in the BABCP Members’ magazine, CBT Today, May 2019 (p21).
Taylor A, Tallon D, Kessler D, Peters TJ, Shafran R, Williams C, et al. An expert consensus on the most effective components of cognitive behavioural therapy for adults with depression: a modified Delphi study. Cogn Behav Ther 2020;49:242–55. https://doi.org/10.1080/16506073.2019.1641146
Author accepted manuscript available at: https://research-information.bris.ac.uk/ws/portalfiles/portal/203250524/2019_07_04_Delphi_paper_revised2_clean_with_figure1.pdf
Stawarz K, Preist C, Tallon D, Wiles N, Kessler D, Turner K, et al. Design considerations for the integrated delivery of cognitive behavioral therapy for depression: user-centered design study. JMIR Ment Health 2020;7:e15972. https://mental.jmir.org/2020/9/e15972
Stawarz K, Preist C, Tallon D, Thomas L, Turner K, Wiles N, et al. Integrating the Digital and the Traditional to Deliver Therapy for Depression: Lessons from a Pragmatic Study. In: Proceedings of the 2020 CHI Conference on Human Factors in Computing Systems. (Honolulu, HI, USA) (CHI’20). Association for Computing Machinery, NY, USA, 1–14. https://dl.acm.org/doi/10.1145/3313831.3376510
Wu Q, Li J, Parrott S, López-López JA, Davies SR, Caldwell DM, et al. Cost-effectiveness of different formats for delivery of cognitive behavioural therapy for depression: a systematic review based economic model. Value Health 2020;23:1662–70. https://doi.org/10.1016/j.jval.2020.07.008
Work package 2: randomised controlled trial
Tallon D, Thomas L, Brabyn S, Ching BCF, Hahn JS, Jude B, et al. Integrated therapist and online CBT for depression in primary care (INTERACT): study protocol for a multi-centre randomised controlled trial. Trials 2023;24:421. https://doi.org/10.1186/s13063-023-07396-9
MacNeill SJ, Wiles NJ, Peters TJ. Multi-centre randomised controlled trial of integrated therapist and online CBT for depression in primary care (INTERACT): Statistical Analysis Plan. 2024. https://research-information.bris.ac.uk/ws/portalfiles/portal/397633546/INTERACT_SAP_v1.pdf
Tallon D, Thomas L, Brabyn S, Ching BCF, Hahn JS, Jude B, et al. Integrated therapist and online cognitive behavioural therapy in addition to usual care versus usual care for depression in primary care in England (INTERACT): a two-group, parallel, multicentre randomised controlled trial. Lancet Prim Care 2026;2: 100164. https://doi.org.10.1016/j.lanprc.2026.100164
Work package 3: economic evaluation
Li J, Wu Q, Parrott S, Tallon D, Wiles NJ. Multi-centre randomised controlled trial of integrated therapist and online CBT for depression in primary care (INTERACT RCT): Health Economics Analysis Plan. 2024. https://research-information.bris.ac.uk/ws/portalfiles/portal/397633247/INTERACT_RCT_HEAP_v1.0_20240104_signed_-Signatures_redacted.pdf
Work package 4: qualitative evaluation
Fox F, Wiles N, Kessler D, Tallon D, Thomas L, Williams C, et al. Patients’ and therapists’ views of integrated online CBT for depression. Health Expect 2024;27:e70002. https://doi.org/10.1111/hex.70002
Fox F, Tallon D, Shafran R, Lanham P, Williams C, Jude B et al. Patients’ reasons for declining a primary care trial of online therapy: a mixed-methods study. BJGP Open 2025;29. https://doi.org/10.3399/bjgpo.2024.0272
Conference presentations
López-López JA, Davies S, Caldwell D, Churchill R, Tallon D, Dawson S, et al. Using Network Meta-analysis to Identify Effective Components of Complex Mental Health Interventions. Oral presentation at Research Synthesis 2019, Dubrovnik, 29 May 2019.
López-López JA, Davies S, Caldwell D, Churchill R, Tallon D, Dawson S, et al. Are All CBT Interventions for Depression Equally Effective? A Component Level Network Meta-analysis. Oral presentation at Annual Meeting of the Society for Research Synthesis Methodology, Bristol, 18 July 2018.
Taylor A, Hollon S, Kessler D, Peters T, Tallon D, Shafran R, et al. Expert Consensus on the Clinically Effective Components of CBT: A Delphi Study. Poster presentation at the 24th International Symposium on Current Issues and Controversies in Psychiatry, Barcelona, 20–22 April 2017.
Taylor A, Hollon S, Kessler D, Peters T, Tallon D, Shafran R, et al. Expert Consensus on the Clinically Effective Components of CBT: A Delphi Study. Poster presentation at the 45th BABCP Annual Conference, Manchester, 25–28 July 2017.
Stawarz K, Preist C, Tallon D, Wiles N, Coyle D. User Experience of CBT Apps for Depression: An Analysis of App Functionality and User Reviews. Invited presentation at the third Symposium on Computing and Mental Health, CHI 2018: Conference on Human Factors in Computing Systems, Montreal, Canada, 21–26 April 2018.
Stawarz K. Designing a Platform for Delivering Integrated Therapy for Depression: Challenges and … More Challenges. Invited presentation at Glasgow Active Minds Conference, Glasgow, 18 July 2018.
Fox F, Tallon D, Jude B, Lanham P, Shafran R, Williams C, et al. Patients’ Reasons for Declining a Trial Evaluating Integrated Online Cognitive Behavioural Therapy for Depression. SAPC Primary Care Mental Health Conference, Bristol, 16 May 2023.
Additional dissemination activities
Katarzyna Stawarz invited to attend a panel discussion on Ethical Web Design at Bath Digital Festival, 25 October 2018. Discussion included the mental health apps review, challenges of working with vulnerable users, and experiences of usability testing in INTERACT.
The results of the Delphi survey were sent to the Delphi participants (October 2019).
Stawarz K, Preist C, Tallon D, Thomas L, Turner K, Wiles N, et al. Integrating the Digital and the Traditional to Deliver Therapy for Depression: Lessons from a Pragmatic Study. Invited presentation at the Irish CHI 2020 online event, 12 June 2020.
Stawarz K. Integrating the Digital and the Traditional to Deliver Therapy for Depression: A User-Centred Design Study. Invited presentation at the UCLIC Research Seminar, 25 November 2020.
Nicola Wiles presented an overview of the INTERACT RCT and linked fMRI imaging study at a NIHR Clinical Research Network event, Bristol, 5 March 2020.
Disclaimers
This article presents independent research funded by the National Institute for Health and Care Research (NIHR). The views and opinions expressed by authors in this publication are those of the authors and do not necessarily reflect those of the NHS, the NIHR, CCF, PGfAR or the Department of Health and Social Care. If there are verbatim quotations included in this publication the views and opinions expressed by the interviewees are those of the interviewees and do not necessarily reflect those of the authors, those of the NHS, the NIHR, the PGfAR programme or the Department of Health and Social Care.