Are Fear Learning Processes Altered in Anxiety and Obsessive-Compulsive Disorder? Insights from the Late Positive Potential, Fear-Potentiated Startle, and Ratings

Fear learning processes are often considered underlying mechanisms in the development and maintenance of various anxiety- and stress-related disorders. However, limited attention has been paid to whether these changes are shared across disorders or certain symptoms. In this context, transdiagnostic research on symptom dimensions is especially relevant, as it addresses the significant symptom overlap and heterogeneity observed in anxiety disorders and obsessive-compulsive disorder (OCD). In the current study, we investigated attentional processes (late positive potential), defensive responding (fear-potentiated startle), and subjective ratings (US-expectancy) in a transdiagnostic sample of participants with OCD (n=38), social phobia (n=39), specific phobia (n=40), and control participants (n=39). We focused on two transdiagnostic anxiety dimensions: anxious arousal and anxious apprehension. A differential fear learning paradigm using geometrical forms was employed, including a habituation, acquisition, generalization, and extinction phase. We observed successful fear acquisition across all outcomes, which generalized to the stimulus most similar to the CS+. While fear responses to the CS+ decreased during extinction, they remained significantly elevated compared to the CS-. The results revealed no differences between the diagnostic groups for neither phase, stimulus nor outcome measure. On a dimensional level, anxious arousal was associated with an increased shock expectancy to the CS+ during acquisition, while depressive symptoms were associated with a higher shock expectancy for both CS+ and CS- during extinction. The unexpected absence of differences between diagnostic groups, along with the modulating dimensional effects, supports the utility of these transdiagnostic symptom dimensions in unraveling altered fear learning processes in internalizing disorders.