Depression: Effectiveness of Collaborative Care Interview with:
David A Richards, PhD
Professor of Mental Health Services Research and NIHR Senior Investigator
University of Exeter Medical School
Sir Henry Wellcome Building
University of Exeter
Washington Singer Building The Queen’s Drive
Exeter EX4 4QQ United Kingdom What are the main findings of the study?

Answer: We found that collaborative care improves depression immediately after treatment compared to usual care, has effects that persist to 12 month follow-up and is preferred bypatients over usual care.

This difference in effect equated to a standardized effect size of 0.26 (95% CI 0.07 to 0.46). More participants receiving collaborative care than those receiving usual care met criteria for recovery (odds ratio 1.67 (95% confidence interval 1.22 to 2.29); number needed to treat=8.4) and response (1.77 (1.22 to 2.58); 7.8 at 4 months.

At 12 months follow up more participants in collaborative care than those in usual care met criteria for recovery (odds ratio 1.88 (95% confidence interval 1.28 to 2.75); number needed to treat=6.5) and response (1.73 (1.22 to 2.44); 7.3.

Collaborative care is as effective in the UK healthcare system—an example of an integrated health system with a well developed primary care sector—as in the US. Were any of the findings unexpected?

Answer: We expected to find that collaborative care was more effective than standard care. Our results are identical to those reported in the latest Cochrane review of collaborative, which contained 79 RCTs. What should clinicians and patients take away from your report?

Answer: Between group differences can obscure response rates in individual patients. We have, therefore, presented the data on meaningful clinical differences using numbers needed to treat and two criteria commonly applied in the depression literature and regarded as clinically meaningful.

These criteria were recovery (falling below a recognized point on the PHQ-9 symptom scale); and response (a 50% reduction in symptoms of depression).

Using these metrics, it is particularly noteworthy that at 12 months, 56% of participants receiving collaborative care “recovered”—15% more than in usual care. Health services would, therefore, need to treat 6.5 patients using collaborative care to produce one additional patient with a sustained recovery compared with usual care.

In other words if GPs think that 15% more people recovered at 12 months is worth having (I certainly do), then they should push to have collaborative care included in the standard care pathways for depression. We see no reason why collaborative care should not be suitable for almost all patients with depression in primary care. The majority of our trial patients presented with complex physical health and mental health co-morbidities, and a substantial number came from socio-economically deprived backgrounds with low social, employment and financial resources. The proportion of people with non-white cultural and ethnic backgrounds was representative of the UK population. What recommendations do you have for future research as a result of this study?

Answer: Future trials should test enhancements of the basic collaborative care model by developing, testing, and delivering better treatments within the effective collaborative care organizational framework, rather than test collaborative care itself, given that the effects of collaborative care are now firmly established.


Clinical effectiveness of collaborative care for depression in UK primary care (CADET): cluster randomized controlled trialRichards DA ,Hill JJ ,Gask L,
Lovell K ,Chew-Graham C ,Bower P ,et al. Clinical effectiveness of collaborative care for depression in UK primary care (CADET): cluster randomised controlled trial. BMJ 2013;347:f4913