From Expectation to Learning: A Mediational Model of Exposure Therapy Outcome in Anxiety Disorders

Negative expectations about treatment outcomes are associated with poorer recovery in anxiety disorders. However, it remains unclear whether patients' expectations about how effective the treatment will be (treatment-specific expectations) mediate the link between generalized negative expectations (i.e., unspecific pessimistic beliefs) and treatment outcomes, and whether these expectations affect outcomes via the learning rate during exposure therapy that is, the extent to which patients update their fear-related beliefs based on corrective experiences. Since treatment-specific expectations may be more modifiable, clarifying these mechanisms could improve interventions. This study therefore investigated whether treatment-specific expectations and learning rate mediate the effect of generalized negative expectations on treatment outcomes.

Data from 605 patients with various anxiety disorders undergoing 12 sessions of manualized exposure therapy were analyzed. Generalized negative expectations at baseline (session 0) were hypothesized to predict treatment outcomes (i.e., symptom severity at posttreatment) via expectations about treatment success measured at session 4 and learning rate during exposure. Depression and anxiety at baseline were covariates. Mediation analyses were conducted using the PROCESS macro with bootstrap confidence intervals.

Generalized negative expectations predicted poorer treatment outcomes (higher symptom severity), mediated by lower expectations about treatment success (β = 0.0375; 95% CI: 0.0088-0.0730). A sequential mediation via these treatment-specific expectations and learning rate was also significant (β = 0.0059; 95% CI: 0.0008-0.0134), even after accounting for baseline symptom levels (R2 = 0.3375).

Targeting both generalized and treatment-specific expectations early in treatment may enhance exposure-based learning and improve clinical outcomes in anxiety disorders.