Return of Threat Expectancy Likelihood After an Exposure Exercise as Dynamic Predictor of Intervention Outcome in Fear of Public Speaking

Although exposure-based Cognitive Behavioral Therapy is generally effective for anxiety disorders, many people do not benefit. A better understanding of treatment predictors is required. This study investigated whether the dynamics of threat expectancy likelihood, which is one of the theorized working mechanisms of exposure, after an exposure exercise would predict subsequent intervention outcome. The short exposure exercise was designed to decrease the likelihood of one idiosyncratic threat expectancy. It was hypothesized that individuals with public speaking anxiety who hold on longer to a decrease in threat expectancy likelihood after the exposure exercise (slower speed of return to equilibrium), show greater benefit from subsequent exposure intervention (i.e., less public speaking anxiety). Participants with subclinical public speaking anxiety (N = 60, M age = 25.42) completed an exposure exercise and momentary assessments in daily life (eight times per day) three days before and four days after the exposure exercise. One week later, they did an online one-session exposure intervention to decrease public speaking anxiety. Result showed that threat expectancy likelihood decreased after the exposure exercise and public speaking anxiety decreased after the intervention. Against expectations, speed of return to expectancy likelihood equilibrium did not predict intervention effects. Potential explanations of null results are discussed, like sampling frequency to measure speed of return to equilibrium and timing of the exposure exercise. Given the potential of dynamic predictors for exposure therapy outcome, more research is needed to examine the conditions in which speed of return to equilibrium predicts subsequent treatment outcome in anxiety.