A Randomized Controlled Pilot Study Exploring the Additive Clinical Effect of Cognitive Bias Modification-Memory in Depressed Inpatients

Background Depression often leads to clinical admission. Stimulating positive memory bias through repeated retrieval can counteract a ruminative depressotypic processing style. Cognitive Bias Modification (CBM)-Memory is a psychological intervention, which was evaluated as possible adjunct treatment for depressed inpatients. Methods A randomized controlled pilot study with a one-week follow-up was implemented to compare the effect of a four-session positive CBM-Memory intervention to a neutral CBM-Memory version. Training-congruent retrieval (as manipulation check), and transfer to rumination (as mechanistic target) and depressive symptoms (self-rated and clinician-rated; indication of clinical relevance) were assessed. Results In the intention-to-treat sample (N = 81, M age =35.6/ SD = 11.9, 60% female), condition-congruent memory retrieval of previously presented target words was found after the training and at follow-up (large effect-sizes). Positive CBM-Memory intervention resulted in sustained recall bias and largest rumination reduction with a small-medium effect size. Additionally, the conditions did not differ significantly on the reduction in depressive symptoms. Conclusions Positive CBM-Memory intervention yielded positive recall bias, which was still present one week later. Additionally, the positive condition did yield more decrease in trait (but not state) rumination, providing some support for rumination as mechanistic target of positive CBM-Memory. However, there was no evidence for transfer of the training effect to depressive symptoms, indicating no superiority on clinical recovery of the positive over the neutral condition. Future research should examine a higher dosage, integration of CBM in the treatment provision, and its long-term effects in a well-powered trial.