Abstract
Fear learning processes are often considered underlying mechanisms in the development and maintenance of 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 these disorders. In the current study, we investigated the late positive potential, fear-potentiated startle, and subjective ratings (US-expectancy) in a transdiagnostic sample (N = 156) including participants with obsessive-compulsive disorder (OCD; n = 38), social anxiety disorder (SAD; n = 39), specific phobia (SP; n = 40), and control participants (n = 39). Anxious arousal, anxious apprehension, and depressive symptoms were examined as relevant core symptom dimensions to these disorders. 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+, the GS+. During extinction, fear responses to the CS+ remained significantly elevated compared to the CS-. Group comparison revealed that patients with SAD rated US-expectancy for the CS- higher during acquisition. On a dimensional level, anxious arousal was associated with increased US-expectancy and startle response for the CS+ during acquisition and increased US-expectancy for the GS+ during generalization. Depressive symptoms were linked to an overall higher US-expectancy during extinction. These findings suggest that individual differences in symptom dimensions, particularly anxious arousal and depressive symptoms, appear to influence fear learning and extinction processes across disorders. This underscores the potential of adopting transdiagnostic approaches in future research and clinical interventions and highlights that the frequently co-occurring comorbid depressive symptoms impact fear extinction, and therefore, should be considered in the treatment of anxiety disorders to enhance therapeutic outcomes.