Efficacy and mechanism of change in transdiagnostic CBT for social anxiety disorder: single case experimental design

Abstract

The main purpose of this study was to evaluate the effectiveness and mechanism of change (MOC) in transdiagnostic cognitive behavior therapy (tCBT) for social anxiety disorder (SAD) using single case experimental design (SCED). The tCBT protocol used is built on Salkovskis proposed MOC in CBT. It involves decreasing an individual’s believability in negative and unrealistic explanation of his problem (theory A) and increasing believability in alternative and more realistic explanation (theory B). SCED with non-concurrent multiple baseline using visual analysis was performed. SCED requires many measures over time and is a promising way to study MOC, especially evaluating temporal changes in treatment. Two participants suffering from SAD received the tCBT. Three questionnaires were submitted in all sessions and four in the beginning, in the middle and in the end of the treatment. Reliable change index scores (RCI) of outcome and process measures were calculated as a secondary analysis. The tCBT was effective in decreasing SAD symptoms for one of the two participants and for both in decreasing depressive symptoms. Believability in theory A decreased and in theory B increased, but more importantly theory A followed symptom change in SPWSS measures and theory B went in opposite direction for both participants. Believability in TMDT decreased for both participants and there was difference in the believability prior-to and post-treatment sessions. TCBT was effective for one of two participants suffering from SAD and targeted cognitions. Visual analysis suggests theory A vs. B as a probable MOC in tCBT, but further study is needed.