Annually, seven percent of the adults suffer from the consequences of depressive disorder and 16 percent once in their lifetime [1
]. In 2020, depression is expected to rank second, after cardiovascular disease, in terms of driving the loss of Disability Adjusted Life Years (DALYs) [2
]. Although several effective treatment options for depression are available, their impact on the societal burden or costs of depression remains limited [3
]. In depressive disorder, a multidisciplinary approach for treatment may be needed, such as disease management. Disease management programs (DMPs) organise healthcare around a specific disease, i.e. depressive disorder, and provide evidence-based treatment as described in multidisciplinary guidelines [4
]. DMPs have been proven effective for the treatment of depressive disorder in US primary care in terms of symptom reduction, quality of life, adherence to medication and attaining remission of depression [5
]. Collaborative care has important characteristics of a DMP and is used for depression management in the US. It organises care around a patient, using a care-manager to give less-costly, qualitative good and effective care.
In a stepped-care arrangement, the intensity or complexity of care is stepped-up only when proven necessary. Patients are first offered an intervention that, while likely to be effective, is relatively easy to implement and carries relatively low cost or side effects. If the effect turns out to be insufficient, treatment is stepped up to a more complex, costly or taxing (in terms of side effects) level. The aim is to ensure that all eligible patients have access to appropriate care, while reserving the most complex treatments for those that have demonstrated not to benefit for more simple treatment. This strategy can be integrated rather easily within collaborative care, which has proven to be an effective treatment model for the treatment of major depression in primary care. Overall effect sizes range from 0.25 (95% CI 0.18-0.32) in the US [9
] to 0.63 (95% CI 0.18-1.07) in the UK health care system [14
]. The longer-term (4 years) effect size was 0.15 (95% CI 0.001-0.31) [15
]. Comparing the costs and benefits of collaborative care is necessary when health policy makers request information on the relative efficiency of health care programs. Two 2006 reviews [8
] addressed presented data on collaborative care, but described DMPs in general and collaborative care as a part of disease management, instead of collaborative care alone. Also, these reviews included studies targeted to healthcare professionals. In the present study, only studies that provided care for patients were included. Besides that, the mentioned reviews provided data of studies that were published until 2005. Several new studies have added economic information, and an update on the collaborative care data therefore is necessary. The aim of this study is to addresses the cost-effectiveness of collaborative care for the treatment of major depressive disorder in primary care.