Behavioral and Magnetoencephalographic Correlates of Fear Generalization Are Associated With Responses to Later Virtual Reality Exposure Therapy in Spider Phobia

Background: Because overgeneralization of fear is a pathogenic marker of anxiety disorders, we investigated whether pretreatment levels of fear generalization in spider-phobic patients are related to their response to exposure-based treatment to identify pretreatment moderators of treatment success.

Methods: A total of 90 patients with spider phobia completed pretreatment clinical and magnetoencephalography assessments, one session of virtual reality exposure therapy, and a posttreatment clinical assessment. Based on the primary outcome (30% symptom reduction in self-reported symptoms), they were categorized as responders or nonresponders. In a pretreatment magnetoencephalography fear generalization paradigm involving fear conditioning with 2 unconditioned stimuli (UCS), we obtained fear ratings, UCS expectancy ratings, and event-related fields to conditioned stimuli (CS: CS-, CS+) and 7 different generalization stimuli on a perceptual continuum from CS- to CS+.

Results: Before treatment, nonresponders showed behavioral overgeneralization indicated by more linear generalization gradients in fear ratings. Analyses of magnetoencephalography source estimations revealed that nonresponders showed a decline of their (inhibitory) frontal activations to safety-signaling CS- and generalization stimuli compared with CS+ over time, while responders maintained these activations at early (<300 ms) and late processing stages.

Conclusions: Results provide initial evidence that pretreatment differences of behavioral and neural markers of fear generalization may act as moderators of later responses to behavioral exposure. Stimulating further research on fear generalization as a potential predictive marker, our findings are an important first step in the attempt to identify patients who may not benefit from exposure therapy and to personalize and optimize treatment strategies for this vulnerable patient group.