Removing Negative Information: The Effects of Working Memory Training on Stress Reactivity in Major Depressive Disorder

Abstract

Major Depressive Disorder (MDD) has been associated with rumination, cognitive biases, and maladaptive responses to stress. Cognitive bias modification (CBM) procedures that train depressed individuals to remove negative material from working memory have recently been developed to decrease rumination and depressive symptoms. However, the effect of such procedures on depressed individuals’ reactions to stressful situations remains largely unexamined. The present study assessed the effects of a CBM procedure on responses to stress in depressed individuals. Twenty-eight participants with MDD were randomly assigned to engage in a weeklong CBM training procedure (Real-RNI [Removing Negative Information] training) or lexical decision task (Sham-RNI training). All participants were administered a stress task after training. Compared to those who received Sham-RNI training, participants who received Real- RNI training exhibited less physiological reactivity—as indexed by heart rate and respiratory sinus arrhythmia—during the verbal component of the stressor. No differences in self-reported stress were observed. Interestingly, participants who received Real-RNI training versus Sham- RNI training did not exhibit greater improvement from pre-training to post-training on CBM trials that required removal of negative information. Nevertheless, given the observed group differences in physiological stress reactivity and the efficiency of RNI-training in terms of time and money, RNI-training appears to be a promising intervention for individuals struggling with MDD.