This paper describes the design of a study to investigate the effectiveness of stepped care for patients with minor and/or major depressive and anxiety disorders in comparison with care as usual in general practice. The following four steps are included in the stepped care model: watchful waiting, guided self-help, PST and pharmacotherapy and/or referral to mental health care. All these interventions are evidence based but there is a lack of studies regarding the effectiveness of stepped care as a whole. Results of this study could offer encouragement for the implementation of an effective stepped care model.
A major strength of this study is that it is a pragmatic randomised trial. In a pragmatic trial, patients and therapists are the same as those seen in daily practice. This means that the sample of patients may be quite heterogeneous (may have mild to severe depression/anxiety with or without psychiatric or somatic co-morbidity) and that the therapists (psychiatric nurses or psychologists) have average qualifications (instead of top level therapists from an academic centre). This enhances external validity which means that the results of this study will reflect the 'real' effects of daily practice. If an intervention is shown to have a significant beneficial effect in a pragmatic trial then it has been shown not only that it can work, but also does work in real life .
This advantage of the study has also some risks. First of all, it is difficult to maintain treatment integrity when conducting a study in day-to-day clinical practice and using personell not specifically hired for research. We hope to minimize this limitation by organizing strict supervision of the care managers.
Secondly, it is possible that there is a bias in our GP recruitment. To conduct this study, we need GPs who work together with a psychiatric nurse. This could mean that these particular GPs are aimed at mental health problems more than their colleagues who work without psychiatric nurse in their practice. If the GPs in our study pay more attention to mental health problems then GPs without psychiatric nurses, then our care as usual might be more adequate then care as usual in general.
Another limitation of our study could be the fact that we choose to recruit people with a diagnosis who do not receive any form of care and/or medication. There is a possibility that these patients have visited the GP before, but were not recognized as mental health patients. These patients might differ in a number of aspects from those who were recognized as mental health patients by their GP. It is possible that this leads to selection bias. To examine this we will conduct a non-response research.
It is widely acknowledged that depression recognition and management in primary care can be improved. As a consequence many collaborative care models, or disease management strategies, have been developed in recent years. The core elements of these care models are (1) an enhanced case management role for nonmedical specialists such as practice nurses and (2) integrated working relationships between primary care and specialist/secondary services . In general these models seem to improve depression treatment . Previous research into a partly implemented stepped care model in secondary services has shown cost-effectiveness compared to care as usual [29, 76]. However, to our knowledge, our trial is the first trial with a fully implemented stepped care model for depression and anxiety treatment in primary care compared to care as usual.