Collaborative care for panic disorder, generalised anxiety disorder and social phobia in general practice: study protocol for three cluster-randomised, superiority trials

Background: People with anxiety disorders represent a significant part of a general practitioner's patient population. However, there are organisational obstacles for optimal treatment, such as a lack of coordination of illness management and limited access to evidence-based treatment such as cognitive behavioral therapy. A limited number of studies suggest that collaborative care has a positive effect on symptoms for people with anxiety disorders. However, most studies are carried out in the USA and none have reported results for social phobia or generalised anxiety disorder separately. Thus, there is a need for studies carried out in different settings for specific anxiety populations. A Danish model for collaborative care (the Collabri model) has been developed for people diagnosed with depression or anxiety disorders. The model is evaluated through four trials, of which three will be outlined in this protocol and focus on panic disorder, generalised anxiety disorder and social phobia. The aim is to investigate whether treatment according to the Collabri model has a better effect than usual treatment on symptoms when provided to people with anxiety disorders. Methods: Three cluster-randomised, clinical superiority trials are set up to investigate treatment according to the Collabri model for collaborative care compared to treatment-as-usual for 364 patients diagnosed with panic disorder, generalised anxiety disorder and social phobia, respectively (total n = 1092). Patients are recruited from general practices located in the Capital Region of Denmark. For all trials, the primary outcome is anxiety symptoms (Beck Anxiety Inventory (BAI)) 6 months after baseline. Secondary outcomes include BAI after 15 months, depression symptoms (Beck Depression Inventory) after 6 months, level of psychosocial functioning (Global Assessment of Functioning) and general psychological symptoms (Symptom Checklist-90-R) after 6 and 15 months. Discussion: Results will add to the limited pool of information about collaborative care for patients with anxiety disorders. To our knowledge, these will be the first carried out in a Danish context and the first to report results for generalised anxiety and social phobia separately. If the trials show positive results, they could contribute to the improvement of future treatment of anxiety disorders.