Changes in threat-related cognitions and experiential avoidance in group-based transdiagnostic CBT for anxiety disorders

•Threat perception and experiential avoidance decreased following group TCBT.•Reductions in threat perception predicted reductions in fear ratings and negative affect.•Reductions in experiential avoidance predicted reductions in fear ratings and negative affect.

Group-based Transdiagnostic Cognitive Behavioral Therapy (TCBT) for anxiety disorders aims to target common factors to produce beneficial effects on multiple anxiety disorders at once. While there is growing evidence that various anxiety disorders can be effectively treated by this approach, the common factors contributing to these treatment effects are not well delineated. In a sample of 48 Veterans who completed Group-based TCBT, the current study examined change in threat perception and change in experiential avoidance pre to post-treatment and as potential mediators of changes in negative affect and personalized fear ratings. Results indicated that both threat perception and experiential avoidance were significantly reduced during treatment. Additionally, reductions in both threat perception and experiential avoidance significantly predicted reductions in negative affect and fear ratings. When change in threat perception and change in experiential avoidance were examined simultaneously, both remained significant predictors of changes in negative affect though only experiential avoidance predicted changes in fear ratings. Thus, both reductions in threat perception and experiential avoidance may mediate the broad treatment effects observed in group-based TCBT. Directions for future research are discussed.