Cognitive bias modification-memory: a computer-based emotional memory training as add-on treatment in patients with major depressive disorder
Depression is an affective disorder with the major symptoms including depressed mood, diminished interest or pleasure, and lack of drive that can lead to a significant reduction in not only the quality of life and life expectancy but also productivity. Driven by these considerable impairments, many efforts have been made to develop helpful treatment options. However, no definitive treatment option for depression has been identified and available treatment capacities are scarce.
Psychological research over the past 50 years has identified cognitive biases in different domains (attention, interpretation, and memory) and has shown that cognitive biases in the processing of emotional information play a role in the development of emotional resilience or emotional vulnerability for depression. Biased memory of negative emotional information is especially salient in the onset and maintenance of depression with relatively enhanced memory for emotionally negative information. It is also known that rumination, the repeated cognitive recollection of one's own stressful circumstances and depressive symptoms, is associated with negative memory bias.
In recent years, computer trainings that attempt to modify these cognitive biases – a practice known as cognitive bias modification (CBM) – have been developed to address anxiety and depression. A new computer-based CBM memory training was designed for the here presented study. The innovation of this work was a focus on reversing negative memory bias by cued repetitive positive retrieval (‘retrieval practice’). In this way, training was intended to address rumination as a possible mechanism behind negative memory bias. While comparable trainings have rarely been conducted with acutely ill patients, this study focused on a clinical population. 82 participants were randomly assigned to either a positive (intervention) or a neutral (control) CBM memory training condition and treated during 4 sessions on the course of one week. In the positive condition, patients were trained to preferentially retrieve positive verbal information and in the neutral condition, they were trained to retrieve neutral information. The main research question in this randomized controlled trial was, whether patients in the positive condition showed a significant decrease in depressive symptoms in contrast to participants in the neutral condition. Of further interest was, whether rumination was also affected by positive CBM memory training. Effects were assessed by the Beck Depression Inventory and by the Hamilton Depression Rating Scale as well as by the Response Style Questionnaire, a measure for rumination. As expected, the positive CBM memory training led to greater reduction in self-assessed depressive symptoms and trait rumination over a period of two weeks compared to the neutral CBM memory training. These findings are promising since a training like that can be implemented as an easy and cost-effective add-on to the current clinical routine treatment of depression.