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Original research
Economic threshold analysis of delivering a task-sharing treatment for common mental disorders at scale: the Friendship Bench, Zimbabwe
  1. Andrew Healey1,
  2. Ruth Verhey2,3,
  3. Iris Mosweu4,
  4. Janet Boadu1,
  5. Dixon Chibanda2,3,
  6. Charmaine Chitiyo2,
  7. Brad Wagenaar5,
  8. Hugo Senra6,7,
  9. Ephraim Chiriseri2,
  10. Sandra Mboweni2,
  11. Ricardo Araya1
  1. 1 Health Services and Population Research, King's College London, London, UK
  2. 2 Friendship Bench, Harare, Zimbabwe
  3. 3 Research Support Trust, Department of Community Medicine, University of Zimbabwe, Harare, Zimbabwe
  4. 4 Department of Health Policy, London School of Economics, London, UK
  5. 5 Department of Epidemiology, University of Washington, Seattle, Washington, USA
  6. 6 Center for Research in Neuropsychology and Cognitive and Behavioral Intervention (CINEICC), University of Coimbra, Coimbra, Portugal
  7. 7 School of Health and Social Care, University of Essex, Colchester, UK
  1. Correspondence to Dr Andrew Healey, Health Services and Population Research, King's College London, London SE5 8AF, UK; andy.healey{at}


Background Task-sharing treatment approaches offer a pragmatic approach to treating common mental disorders in low-income and middle-income countries (LMICs). The Friendship Bench (FB), developed in Zimbabwe with increasing adoption in other LMICs, is one example of this type of treatment model using lay health workers (LHWs) to deliver treatment.

Objective To consider the level of treatment coverage required for a recent scale-up of the FB in Zimbabwe to be considered cost-effective.

Methods A modelling-based deterministic threshold analysis conducted within a ‘cost-utility’ framework using a recommended cost-effectiveness threshold.

Findings The FB would need to treat an additional 3413 service users (10 per active LHW per year) for its scale-up to be considered cost-effective. This assumes a level of treatment effect observed under clinical trial conditions. The associated incremental cost-effectiveness ratio was $191 per year lived with disability avoided, assuming treatment coverage levels reported during 2020. The required treatment coverage for a cost-effective outcome is within the level of treatment coverage observed during 2020 and remained so even when assuming significantly compromised levels of treatment effect.

Conclusions The economic case for a scaled-up delivery of the FB appears convincing in principle and its adoption at scale in LMIC settings should be given serious consideration.

Clinical implications Further evidence on the types of scale-up strategies that are likely to offer an effective and cost-effective means of sustaining required levels of treatment coverage will help focus efforts on approaches to scale-up that optimise resources invested in task-sharing programmes.

  • adult psychiatry
  • anxiety disorders
  • depression & mood disorders

Data availability statement

Data are available upon reasonable request. Data are available on reasonable request.

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Data availability statement

Data are available upon reasonable request. Data are available on reasonable request.

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  • Contributors AH led on the design of the economic evaluation, analysis and drafting the manuscript. AH is guarantor and responsible for the overall content of the paper. RA was the principal investigator of the wider OptFB project. RV and DC were leading the project locally. IM and JB contributed to the earlier stages of the economic analysis. RV, IM, JB, DC, CC, BW, HS, EC, SM and RA all contributed to various drafts of the manuscript. All coauthors have approved the final version.

  • Funding This study formed part of a wider research project: Optimising implementation strategies of the first scale-up of a primary care psychological intervention for common mental disorders in Sub-Saharan Africa: The Friendship Bench (OptFB). The work is supported by the Global Alliance for Chronic Diseases (GACD) through the Medical Research Council (MRC)/UKRI (grant number MRC UKRI MR/S004270/1). AH is supported by the National Institute for Health (NIHR) Applied Research Collaboration (ARC) South London at King’s College Hospital NHS Foundation Trust. AH is also a member of King’s Improvement Science, which offers cofunding to the NIHR ARC South London and comprises a specialist team of improvement scientists and senior researchers based at King’s College London. Its work is funded by King’s Health Partners (Guy’s and St Thomas’ NHS Foundation Trust, King’s College Hospital NHS Foundation Trust, King’s College London, and South London and Maudsley NHS Foundation Trust), Guy’s and St Thomas’ Charity, and the Maudsley Charity.

  • Competing interests None declared.

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

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