Change in Negative Attention Bias Mediates the Association Between Attention Bias Modification Training and Depression Symptom Improvement

What is the public health significance of this article? Prior work has shown that ABMT reduces depression but it is unclear why this is so. The present study confirms that ABMT works by reducing a tendency to focus attention on negative information, which in turn reduces symptoms of depression. Objective: Attention bias modification training (ABMT) is purported to reduce depression by targeting and modifying an attentional bias for sadness-related stimuli. However, few tests of this hypothesis have been completed. Method: The present study examined whether change in attentional bias mediated a previously reported association between ABMT condition (active ABMT, sham ABMT, assessments only; N = 145) and depression symptom change among depressed adults. The preregistered, primary measure of attention bias was a discretized eye-tracking metric that quantified the proportion of trials where gaze time was greater for sad stimuli than neutral stimuli. Results: Contemporaneous longitudinal simplex mediation indicated that change in attentional bias early in treatment partially mediated the effect of ABMT on depression symptoms. Specificity analyses indicated that in contrast to the eye-tracking mediator, reaction time assessments of attentional bias for sad stimuli (mean bias and trial level variability) and lapses in sustained attention did not mediate the association between ABMT and depression change. Results also suggested that mediation effects were limited to a degree by suboptimal measurement of attentional bias for sad stimuli. Conclusion: When effective, ABMT may improve depression in part by reducing an attentional bias for sad stimuli, particularly early on during ABMT.