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Influence of initial severity of depression on effectiveness of low intensity interventions: meta-analysis of individual patient data

BMJ 2013; 346 doi: (Published 26 February 2013) Cite this as: BMJ 2013;346:f540
  1. Peter Bower, professor of health services research1,
  2. Evangelos Kontopantelis, research fellow1,
  3. Alex Sutton, professor of medical statistics2,
  4. Tony Kendrick, professor of primary care and dean3,
  5. David A Richards, professor of mental health services research4,
  6. Simon Gilbody, professor of psychological medicine & health services research5,
  7. Sarah Knowles, research fellow1,
  8. Pim Cuijpers, professor of clinical psychology6,
  9. Gerhard Andersson, professor of clinical psychology7,
  10. Helen Christensen, professor and executive director8,
  11. Björn Meyer, research director and honorary research fellow9,
  12. Marcus Huibers, professor of psychotherapy10,
  13. Filip Smit, professor of public mental health11,
  14. Annemieke van Straten, professor in clinical psychology6,
  15. Lisanne Warmerdam, research fellow6,
  16. Michael Barkham, professor of clinical psychology12,
  17. Linda Bilich, research fellow13,
  18. Karina Lovell, professor of mental health14,
  19. Emily Tung-Hsueh Liu, associate professor of clinical psychology15
  1. 1NIHR School for Primary Care Research, Manchester Academic Health Science Centre, University of Manchester, Manchester M13 9PL, UK
  2. 2Department of Health Sciences, University of Leicester, Leicester, UK
  3. 3Hull York Medical School, University of York, York, UK
  4. 4Sir Henry Wellcome Building, University of Exeter Medical School, University of Exeter, Exeter, UK
  5. 5Department of Health Sciences, University of York & Hull York Medical School (HYMS)
  6. 6Department of Clinical Psychology and EMGO Institute for Health and Care Research, VU University and VU University Medical Center Amsterdam, Amsterdam, Netherlands
  7. 7Department of Behavioural Sciences and Learning, Linköping University, Linköping, Sweden, and Karolinska Institute, Stockholm, Sweden
  8. 8Black Dog Institute, University of New South Wales, Randwick NSW, Australia
  9. 9Research Department, GAIA AG, Hamburg, Germany, and Department of Psychology, City University, London, UK
  10. 10Department of Clinical Psychology, VU University Amsterdam, and Department of Clinical Psychological Science, Maastricht University
  11. 11Department of Epidemiology and Biostatistics and EMGO Institute for Health and Care Research, VU University Medical Center
  12. 12Centre for Psychological Services Research, University of Sheffield, Sheffield, UK
  13. 13University of Wollongong, Wollongong NSW, Australia
  14. 14School of Nursing, Midwifery and Social Work, University of Manchester
  15. 15College of Medicine, Fu-Jen Catholic University, Taiwan
  1. Correspondence to: P Bower peter.bower{at}
  • Accepted 11 January 2013


Objective To assess how initial severity of depression affects the benefit derived from low intensity interventions for depression.

Design Meta-analysis of individual patient data from 16 datasets comparing low intensity interventions with usual care.

Setting Primary care and community settings.

Participants 2470 patients with depression.

Interventions Low intensity interventions for depression (such as guided self help by means of written materials and limited professional support, and internet delivered interventions).

Main outcome measures Depression outcomes (measured with the Beck Depression Inventory or Center for Epidemiologic Studies Depression Scale), and the effect of initial depression severity on the effects of low intensity interventions.

Results Although patients were referred for low intensity interventions, many had moderate to severe depression at baseline. We found a significant interaction between baseline severity and treatment effect (coefficient −0.1 (95% CI −0.19 to −0.002)), suggesting that patients who are more severely depressed at baseline demonstrate larger treatment effects than those who are less severely depressed. However, the magnitude of the interaction (equivalent to an additional drop of around one point on the Beck Depression Inventory for a one standard deviation increase in initial severity) was small and may not be clinically significant.

Conclusions The data suggest that patients with more severe depression at baseline show at least as much clinical benefit from low intensity interventions as less severely depressed patients and could usefully be offered these interventions as part of a stepped care model.


  • Contributors: The original idea for the research was developed by PB, SG, DR, and TK. The database of individual patient data was developed by PB, and the analysis conducted by EK with support from AS. SK conducted quality assessments and other data extraction. PC, GA, HC, BM, MH, FS, AvS, LW, MB, LB, KL and ETL all supplied data and assisted with queries. PB and EK wrote the paper. All authors commented on drafts. PB is the guarantor.

  • Funding: The Targeting Depression Interventions In Stepped care (TARDIS) study was funded as part of the UK National Institute of Health Research (NIHR) School for Primary Care Research. The research team were independent from the funding agency. The views expressed in this publication are those of the authors and not necessarily those of the NHS, NIHR, or Department of Health.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at and declare: BM is currently a full time employee of GAIA AG, Hamburg, Germany, a company that owns and developed one of the low intensity interventions considered in this paper. PB has acted as a paid scientific consultant to the British Association of Counselling and Psychotherapy. All other authors declare no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; and no other relationships or activities that could appear to have influenced the submitted work .

  • Ethical approval: Not required.

  • Data sharing: No additional data available.

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