Fear and Safety Learning in Anxiety Spectrum Disorders: An Updated Meta-Analysis

Fear learning processes are assumed to play a key role in the pathogenesis of anxiety disorders, a heterogeneous group of disorders characterized by excessive anxiety and avoidance behavior. While some disorders receive more attention in fear and safety learning research, others remain understudied. Heterogeneity in concepts, measures, and designs within the field of fear learning further contribute to inconsistent study outcomes. Addressing these challenges, we conducted a systematic meta-analysis, adhering to the PRISMA guidelines, to examine differences in fear conditioning processes between anxiety patients and healthy participants, updating the meta-analysis by Duits et al. (2015). We extended the previous analyses by conducting subgroup analyses for different types of anxiety disorders, and distinguished between different physiological and behavioral outcome measurements. This meta-analysis includes 76 studies published between 1986 and 2022 with data from 1.974 patients with anxiety disorders and 3.154 healthy participants. The results support differences in fear acquisition and extinction in individuals with anxiety disorders compared with healthy participants. More specifically, patients with anxiety disorders showed heightened responses to the CS- in both physiological and behavioral measures during fear acquisition, and increased aversiveness ratings for the CS+. Following extinction learning, patients with anxiety disorders showed increased threat expectancy and affect ratings to both CS+ and CS-, alongside stronger SCR to the CS- compared with healthy participants. These findings suggest that individuals with anxiety disorders may exhibit amplified responses to safety cues along with delayed extinction of learned fear associations. These changes may lead to increased sensitivity in acquiring and detecting fear and a slower extinction process, resulting in more enduring anxiety responses. These characteristics are consistent with a "better-safe-than-sorry" information processing strategy linked to anxiety and susceptibility to anxiety. We integrate our results into the current literature on fear and safety learning and discuss possible underlying mechanisms. Furthermore, we explicitly mention current challenges, and give recommendations how they can be addressed.