Pretreatment anhedonia as a predictor of exposure-based anxiety treatment outcomes.

Reward processes can reinforce extinction learning and aide cognitive processes involved with inhibitory learning. Anhedonia, characterized by deficits in reward incentivization, hedonic response, and learning, may therefore predict worse treatment outcomes. The current study examined associations between pretreatment self-reported anhedonia and several measures of anxiety symptom severity and treatment outcomes in a naturalistic exposure-based treatment setting. We used multilevel models to examine the relationship between pretreatment anhedonia with change in general treatment response and disorder-specific symptoms for obsessive compulsive disorder (OCD), post-traumatic stress disorder (PTSD), generalized anxiety disorder (GAD), social anxiety disorder (SAD), and panic disorder (PD). Consistent with hypotheses, pretreatment anhedonia severity was associated with higher pretreatment anxiety symptom severity across all measures. However, inconsistent with hypotheses, higher anhedonia scores were associated with greater symptom improvement across treatment for OCD, GAD, and PD, and had no significant relationships with diagnosis-general outcome measures, PTSD symptoms, or SAD symptoms. In sensitivity analyses including number of sessions, higher anhedonia was associated with more sessions across treatment and anhedonia no longer significantly predicted OCD or GAD treatment outcomes when controlling for treatment dose. Together, findings suggest that individuals with higher pretreatment anhedonia still respond to exposure therapy for anxiety disorders, but may require more sessions. More broadly, results highlight challenges in translating laboratory research to naturalistic clinical settings and the need for intensive longitudinal studies that can assess the role of reward processes in exposure therapy.