The overall aim of this thesis was to examine the effectiveness of generic metacognitive therapy (MCT), a transdiagnostic treatment model, and disorder-specific cognitive behavioral therapy (CBT) in the treatment of comorbid anxiety disorders. The term comorbid anxiety disorders is a designation of a phenomenon that consists of several anxiety disorders or more severe and chronic symptoms compared to a single anxiety disorder. The thesis consists of three studies.
Study I evaluated the generic metacognitive model in the treatment of a highly comorbid and severe anxiety disorder patient. Readministration of the Mini International Neuropsychiatric Interview (MINI) at 1-year follow-up revealed that the patient no longer met diagnostic criteria for any of the prior ICD-10 diagnoses. The patient had a reliable change in BDI and SCL-90, and it was found that at 1-year follow-up the patient scores were in the normal range. The results indicated that the metacognitive model was feasible for treating comorbid anxiety disorders.
Study II evaluated the effectiveness of MCT and CBT in a randomized controlled trial encompassing 90 patients with either SAD, PD/A or PTSD. From pretreatment to post-treatment, there were significant differences in favor of MCT on self-report measures, but not on the primary interview-based outcome measure. At 1-year follow-up, no differences were present. There were no differences in effect on comorbid diagnoses and symptoms between the treatments. The results indicate that adoption of MCT for patients with comorbid anxiety disorders may be warranted.
Study III investigated the mechanism of change in CBT and MCT using multilevel modeling and a proper disaggregation of the predictor variable in within- and between-person effects. The results indicated that metacognitions decreased more in MCT than CBT over the course of therapy. There was a within-person effect of cognitions and metacognitions on predicting anxiety. However, there was no interaction with treatment condition. There was a reciprocal relationship between anxiety and metacognitions and anxiety and cognitions. The reciprocal relationship of anxiety on metacognitions was larger in MCT than in CBT. Thus, both cognition and metacognition are central targets for treatment, as specified by their respective psychological models, and clinicians who target these processes could expect reductions in anxiety.