Randomized controlled trial of transdiagnostic group treatments for primary care patients with common mental disorders.

Background: The purpose was to test the effectiveness of two transdiagnostic group interventions compared to care as usual (CAU) for patients with anxiety, depressive or stress-related disorders within a primary health care context.

Objectives: To compare the effects of cognitive-based-behavioural therapy (CBT) and multimodal intervention (MMI) on the quality of life and relief of psychological symptoms of patients with common mental disorders or problems attending primary health care centre.

Methods: Patients (n = 278), aged 18-65 years, were referred to the study by the GPs and 245 were randomized to CAU or one of two group interventions in addition to CAU: (i) group CBT administered by psychologists and (ii) group MMI administered by assistant nurses. The primary outcome measure was the Mental Component Summary score of short form 36. Secondary outcome measures were Perceived Stress Scale and Self-Rating Scale for Affective Syndromes. The data were analysed using intention-to-treat with a linear mixed model.

Results: On the primary outcome measure, the mean improvement based on mixed model analyses across post- and follow-up assessment was significantly larger for the MMI group than for the CBT (4.0; P = 0.020) and CAU (7.5; P = .001) groups. Participants receiving CBT were significantly more improved than those in the CAU group. On four of the secondary outcome measures, the MMI group was significantly more improved than the CBT and CAU groups. The course of improvement did not differ between the CBT group and the CAU group on these measures.

Conclusions: Transdiagnostic group treatment can be effective for patients with common mental disorders when delivered in a primary care setting. The group format and transdiagnostic approach fit well with the requirements of primary care.