Individual differences in threat expectancy type and strength and the influence on exposure treatment success in PTSD patients

Exposure therapy is an effective treatment for post-traumatic stress disorder (PTSD), yet a substantial number of patients fails to reach symptom relief. Therefore, a deeper understanding of the underlying mechanisms may help improve the treatment. Inhibitory learning has been a recently developed approach, stating that new fear associations must be actively developed. One proposed strategy has been that of expectancy violation, in which threat expectancies are actively challenged during exposure. Actively experiencing a mismatch between expectancy and reality is supposed to benefit learning and thus improve exposure success, yet results have been mixed. The aim of this study was to expose the mechanisms of expectancy violation by analyzing the types of expectancies experienced by PTSD patients. Furthermore, the effects of the strength of these expectancies and the extent to which they change in strength during exposure on treatment success was tested. In a clinical assay,...Show moreExposure therapy is an effective treatment for post-traumatic stress disorder (PTSD), yet a substantial number of patients fails to reach symptom relief. Therefore, a deeper understanding of the underlying mechanisms may help improve the treatment. Inhibitory learning has been a recently developed approach, stating that new fear associations must be actively developed. One proposed strategy has been that of expectancy violation, in which threat expectancies are actively challenged during exposure. Actively experiencing a mismatch between expectancy and reality is supposed to benefit learning and thus improve exposure success, yet results have been mixed. The aim of this study was to expose the mechanisms of expectancy violation by analyzing the types of expectancies experienced by PTSD patients. Furthermore, the effects of the strength of these expectancies and the extent to which they change in strength during exposure on treatment success was tested. In a clinical assay, participants (N = 60) were randomized across two groups, which both received exposure therapy. The experimental group’s exposure treatment was designed to enhance expectancy violation. In both groups, PTSD symptoms were measured at baseline and follow- up, and threat expectancies were measured right before and right after exposure. Results showed that both threat expectancies and PTSD symptoms reduced significantly. However, baseline expectancy strength did not have a significant effect on the amount of PTSD symptom reduction, both in the total and the experimental group. Furthermore, the amount of expectancy change did not predict PTSD symptom reduction either. A full ranking of expectancy types was provided.Show less

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Individual differences in threat expectancy type and strength and the influence on exposure treatment success in PTSD patients