Examining Positive and Negative Affect as Outcomes and Moderators of Cognitive-Behavioral Therapy and Acceptance and Commitment Therapy for Social Anxiety Disorder

Traditional cognitive-behavioral therapy (CBT) for anxiety disorders has been designed to target reductions in negative affect (NA) associated with defense-related processes. However, a subset of anxiety disorders, including social anxiety disorder (SAD), are also characterized by low positive affect (PA) resulting from separate deficits in appetitive-related processes. In contrast to CBT, "third-wave" approaches, such as acceptance and commitment therapy (ACT), align more consistently with motivational processes and, as a result, PA. However, the differential effect of CBT and ACT on PA and NA has yet to be investigated. Using secondary data from a randomized controlled trial, the present study sought to compare CBT's (n = 45) and ACT's (n = 35) effect on PA and NA in SAD. Findings were compared to a wait-list (WL) control condition (n = 31), as well as normative data from a general adult sample. Baseline PA and NA were also examined as moderators and predictors of theory-relevant treatment outcomes. NA decreased significantly in both CBT and ACT from pre to posttreatment. Although ACT outperformed WL in reducing NA, this effect was not observed for CBT. PA increased significantly in both CBT and ACT from pre to posttreatment, with neither ACT nor CBT outperforming WL in increasing PA. Neither PA nor NA were found to moderate theoretically relevant treatment outcomes. Findings suggest that ACT and CBT share common treatment mechanisms, making them more similar than distinct. Further efforts should be focused on optimizing CBT's and ACT's influence on threat and reward learning, and elucidating common processes of change.