Effects of attention bias modification for anxiety: Neurophysiological indices and moderation by symptom severity.

• This RCT aims to reduce anxiety symptom severity via a 4-week attention bias modification (ABM) vs placebo control training. • We examined treatment effects on attention bias (AB) via ERPs and the moderating role of baseline anxiety severity. • ABM reduced symptom severity among those with higher anxiety and modulated ERP indices of AB. Attention bias modification (ABM) aims to decrease anxiety symptom severity through the reduction of threat-related attention bias (AB). Individual differences in treatment response and poor measurement reliability of AB have called its clinical promise into question. The current study examined whether individual differences in anxiety severity at baseline moderated treatment response, and employed both behavioral and neurophysiological metrics of AB. Participants (N = 99) were randomly assigned to four weeks of ABM or placebo control training (PT). Self-reported anxiety symptom severity, and AB metrics and ERPs generated during the dot probe task were collected at baseline (Time 1), one-week post-intervention (Time 5), and at a three-month follow-up (Time 6). ABM, relative to PT, reduced ERPs indexing attention discrimination (N170) and increased ERPs indexing salience tracking (P3). Increases in P3 were associated with ABM-related reductions in anxiety. Anxiety severity was reduced following ABM, but only among those with higher baseline anxiety symptom severity. ABM effectively reduced symptom severity among those with higher levels of anxiety, and modulated neurophysiological indices of AB. Results provide evidence for attention-relevant ERPs as outcomes of ABM treatment responsivity and suggest that ABM may be most beneficial for those with more severe anxiety symptoms. [ABSTRACT FROM AUTHOR]