Response Patterns to Critical Session in Metacognitive Therapy as a Predictor of Treatment Outcome in Comorbid Anxiety Disorders

Objective: Negative beliefs about worry are a transdiagnostic maintaining factor of anxiety, addressed in an early treatment session of Metacognitive Therapy. This study examined the individual temporal response to this ‘critical session’ to predict overall treatment outcome. Based on Dynamic Systems Theory, it was expected that patients who retained an improvement in negative beliefs after the critical session, benefitted more from the overall treatment. Method: Treatment-resistant patients with comorbid anxiety disorders who followed Metacognitive Therapy and showed a drop in negative beliefs about worry after the critical session were selected (N = 45, 73.3% women, M age = 44.5). Negative beliefs about worry up to two weeks after the critical session, measured with the Metacognitions Questionnaire-30, were used to determine response patterns. Anxiety symptoms were measured at start, end, and one year after treatment using the Beck Anxiety Inventory. Analyses were pre-registered. Results: Most patients (65.1%) were classified as persistent responder (retaining improvement after critical session), as opposed to reversed responders, but this dichotomous predictor did not predict treatment outcomes. In contrast, individual slopes of negative beliefs about worry after the critical session positively predicted anxiety symptoms and clinically relevant improvement posttreatment but not one year follow-up. Conclusions: Holding on longer to an improvement in negative beliefs about worry predicted better treatment outcomes. This predictor could provide insight into whether patients have mastered a theorized, critical element for symptom improvement in MCT, which could be used to implement adjustments to the treatment plan to improve individual treatment effectiveness.