Collaborative Care: Depression Initiative in Primary care.

Background:
Depressive disorder is today one of the two most burdensome disorders. Evidence-based treatments of depressive disorder are already available, but are used insufficiently and with less results than possible. Prior research in the USA has shown good results in the treatment of depressive disorder by using a collaborative care approach with Problem Solving Treatment (PST) and an antidepressant treatment algorithm, and prior research in the UK has also shown good results with PST. These treatment strategies may very well work in the Netherlands too, even though health care systems differ between countries.

Methods/design:
The present study is a two armed cluster-randomized clinical trial, with randomization between general practitioner (GP) practices. The aim of the trial is an evaluation of the treatment of depressive disorder in primary care in the Netherlands by means of an adapted collaborative care framework including contracting and adherence improving strategies, and combined with the option of PST and/or an antidepressant medication following a treatment algorithm. Forty GP practices will be randomised between the intervention group or control group. Patients are included who are diagnosed with moderate to severe depression based on DSM-IV criteria. The intervention group receives treatment based on the collaborative care approach, the control group receives care as usual (CAU). Baseline measures and follow up measures (3, 6 and 12 months) are assessed using questionnaires and interview. The primary outcome measure is response as measured by the PHQ9 and IDS-SR. Secondary outcome measures are remission as measured by the PHQ9 and IDS-SR, effect of chronic physical illness as key effect modifier, and cost-effectiveness as measured with the TiC-P, EQ-5D and the SF-36.

Discussion:
In the current study, an American model to enhance care for depressive patients, the collaborative care model, will be evaluated for effectiveness in the primary care setting. If effective across the Atlantic and across different health care systems, it is likely to be a good strategy to implement in the treatment of major depressive disorder in the Netherlands.

The aim of the current randomized clinical trial (RCT) is a cost-effectiveness analyses of a collaborative care approach compared to Care as Usual (CAU). The collaborative care approach is expected to be more effective and cost-effective than CAU.

The collaborative care approach includes care management, contracting, adherence improving strategies, manual guided self help and lifestyle interventions, Problem Solving Treatment, and an antidepressant treatment algorithm; the treatment plan is set based on patient preferences.