Supplementary Material for: Attentional Bias Modification in Posttraumatic Stress Disorder: A Randomized Controlled Trial

<b><i>Background:</i></b> Attentional bias modification (ABM) is a new treatment for anxiety disorders. Three randomized controlled clinical trials have shown positive effects of ABM in social anxiety disorder and generalized anxiety disorder. This study investigated the efficacy of ABM in outpatients with chronic posttraumatic stress disorder (PTSD). <b><i>Methods:</i></b> Randomized controlled double-blind trial (n = 102). ABM and control treatment consisted of eight 20-min sessions over the course of 3 weeks. Symptoms and attentional bias were assessed before and after treatment and at 3-week follow-up. <b><i>Results:</i></b> ABM and the control treatment were equally effective in reducing the symptoms of PTSD. The effect sizes of the improvement (from before to after treatment) were 0.66 for ABM and 0.46 for the control treatment, which is comparable to the effect sizes of pill-placebos in pharmacotherapy trials of chronic PTSD. Both treatments did not affect attentional bias. The acceptability and tolerability of ABM was moderate. <b><i>Conclusions:</i></b> This version of ABM is not an effective treatment of PTSD.