Inside Exposure: Tracking Fear and Threat Expectancy Dynamics Within and Between Exposure Sessions for Anorexia Nervosa.

objectiveAnxiety and avoidance behaviors are increasingly recognized as key drivers of anorexia nervosa. Exposure therapy, rooted in the inhibitory learning model, targets these drivers by violating threat expectancies. This translational study investigated the dynamics of fear and threat expectancies within and between 417 individualized exposure sessions for female patients with anorexia nervosa. It was hypothesized that the violation of individual threat expectancies during exposure experiments would reduce threat expectancies and fears, both within and between sessions. Whether the focus of the exposure experiments (eating-related or body-related) influenced outcomes was also examined.

methodIndividually tailored exposure sessions were designed and performed to challenge idiosyncratic threat expectancies. A total of 2895 datapoints from 417 sessions were collected and analyzed.

resultsLinear mixed models revealed significant within-session reductions in threat expectancies and fear levels following the exposure experiments and postexposure discussions of experiences and outcomes. Both fear levels and threat expectancies also decreased across sessions. Notably, body-related exposures evoked stronger fears and threat expectancies than eating-related exposures, though both types of exposure led to similar threat expectancy and fear reductions over time. DISCUSSION: These fine-grained analyses of the dynamics of fears and threat expectations during exposure sessions highlight threat expectancy change as a likely mechanism of therapeutic change. The study supports the use of exposure in the treatment of anorexia nervosa to break avoidance cycles and promote recovery.