Time course of pupillary response to threat words before and after attention bias modification for transdiagnostic anxiety disorders: A randomized controlled trial

INTRODUCTION: Altered attention to threatening stimuli at initial and sustained stages of processing may be dissociable dimensions that influence the development and maintenance of transdiagnostic symptoms of anxiety, such as vigilance, and possibly require distinct intervention. Attention bias modification (ABM) interventions were created to implicitly train attention away from threatening stimuli and have shown efficacy in treating anxiety. ABM alters neurocognitive functioning during initial stages of threat processing, but less is known regarding effects of ABM on neural indices of threat processing at sustained (i.e., intermediate and late) stages, or if ABM‐related neural changes relate to symptom response. The current study utilized pupillary response as a temporally sensitive and cost‐effective peripheral marker of neurocognitive response to ABM. MATERIALS AND METHODS: In a randomized controlled trial, 79 patients with transdiagnostic anxiety provided baseline data, 70 were randomized to receive eight sessions of twice‐weekly ABM (n = 49) or sham training (n = 21), and 65 completed their assigned treatment condition and returned for post‐training assessment. RESULTS: Among ABM, but not sham, patients, pupillary response to threat words during initial and intermediate stages decreased from pre‐ to post‐training. Pre‐ to post‐training reductions in intermediate and late pupillary response to threat were positively correlated with reductions in patient‐reported vigilance among ABM, but not sham, patients. CONCLUSIONS: All measured stages of threat processing had relevance in understanding the neural mechanisms of ABM, with overlapping yet dissociable roles exhibited within a single neurophysiological marker across an initial–intermediate–late time continuum. Pupillometry may be well suited to measure both target engagement and treatment outcome following ABM.