Differential effects of cognitive restructuring and cognitive defusion in anxiety disorders : a single subject multiple baseline experimental study

Abstract

Objectives: Although both cognitive behavioral therapy (CBT) and acceptance and commitment therapy (ACT) are proven effective treatments for anxiety disorders, their underlying mechanisms of change remain unclear. Few researchers have isolated and compared the effects of cognitive restructuring (CR) and cognitive defusion (CD), which are core cognitive treatment modules embedded within CBT and ACT packages. The aim of this study was to examine their postulated cognitive mechanisms of change and effectiveness in reducing anxiety symptoms in a clinical sample with anxiety disorders. Method: Participants with anxiety disorders were recruited from a Hong Kong outpatient setting. A three-phase counterbalanced multiple-baseline single-subject experimental design was used to investigate the effects of three-session CR and CD interventions on anxiety symptoms, CBT-specific measures (i.e., cognitive reappraisal and cognitive distortions), and ACT-specific measures (i.e., cognitive fusion and believability of anxious thoughts). Hypothesis: It was hypothesized that ACT-specific measures would be changed only by CD, whereas CBT-specific cognitive process measures would be changed only by CR. Results: Nine out of the 10 recruited participants completed treatments. The hypothesis was partially supported: ACT-specific variables were improved only by CD, supporting specific effects of CD on ACT-specific cognitive processes. However, CR and CD’s effects on CBT-specific measures contradicted the hypothesis: Cognitive reappraisal was altered by both interventions, while cognitive distortions were affected by neither. Moreover, CD outperformed CR in reducing anxiety symptoms. Implications: This study adds to existing knowledge on mechanisms of change underlying cognitive interventions. It also demonstrated the value of a single-subject experimental design as a valid and cost-effective research method in clinical settings. Theoretical, clinical and methodological implications of the findings were discussed.