Collaborative care for depression in UK primary care: a randomized controlled trial

Psychol Med. 2008 Feb;38(2):279-87. doi: 10.1017/S0033291707001365. Epub 2007 Sep 6.


Background: Collaborative care is an effective intervention for depression which includes both organizational and patient-level intervention components. The effect in the UK is unknown, as is whether cluster- or patient-randomization would be the most appropriate design for a Phase III clinical trial.

Method: We undertook a Phase II patient-level randomized controlled trial in primary care, nested within a cluster-randomized trial. Depressed participants were randomized to 'collaborative care' - case manager-coordinated medication support and brief psychological treatment, enhanced specialist and GP communication - or a usual care control. The primary outcome was symptoms of depression (PHQ-9).

Results: We recruited 114 participants, 41 to the intervention group, 38 to the patient randomized control group and 35 to the cluster-randomized control group. For the intervention compared to the cluster control the PHQ-9 effect size was 0.63 (95% CI 0.18-1.07). There was evidence of substantial contamination between intervention and patient-randomized control participants with less difference between the intervention group and patient-randomized control group (-2.99, 95% CI -7.56 to 1.58, p=0.186) than between the intervention and cluster-randomized control group (-4.64, 95% CI -7.93 to -1.35, p=0.008). The intra-class correlation coefficient for our primary outcome was 0.06 (95% CI 0.00-0.32).

Conclusions: Collaborative care is a potentially powerful organizational intervention for improving depression treatment in UK primary care, the effect of which is probably partly mediated through the organizational aspects of the intervention. A large Phase III cluster-randomized trial is required to provide the most methodologically accurate test of these initial encouraging findings.

Publication types

  • Clinical Trial, Phase II
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cooperative Behavior
  • Demography
  • Female
  • Humans
  • Male
  • Mental Disorders / diagnosis*
  • Mental Disorders / therapy*
  • Mental Health Services* / organization & administration
  • Patient Care Team*
  • Primary Health Care / methods*
  • Treatment Outcome
  • United Kingdom
  • Workforce