Acceptance and mindfulness as mediators of change in an acceptance-based behavior therapy and a non-directive supportive therapy for generalized anxiety disorder

Abstract

ABSTRACT Objective: Acceptance and mindfulness have been focused on as core clinical targets of evidence-based psychotherapeutic approaches for generalized anxiety disorder (GAD), such as acceptance-based behavior therapy (ABBT). Methods: In the present study, we examined whether experiential avoidance (EA) and the five facets of mindfulness mediated clinical change in GAD core symptoms (i.e., worry and generalized anxiety) in 92 patients who received 10 sessions of either group ABBT or nondirective supportive group therapy (NDST). A mediation model was used to examine the relative magnitude of the indirect effects associated with each of the proposed mediators. Results: ABBT, relative to NDST, had a significantly larger improvement on two mindfulness facets (describing and non-judgment) from pre- to mid-treatment. Several process variables were significantly associated with changes in anxiety and worry levels between midtreatment and posttreatment. Nevertheless, only one mindfulness facet (Describing) acted as a mediator for the later reduction in one of the outcomes (i.e., generalized anxiety). Conclusions: Our findings are similar to those from previous research using time-lag analysis. There is a need to explore and test the relations between these and competing processes in relation to GAD symptoms in both controlled experiment settings and larger controlled trials.