Temporal dynamics of CBT emotion regulation training in patients with major depression using ecological momentary assessment

Rumination is known to have a negative impact on both the process of psychotherapy as well as the development of depressive symptoms and even the probability of relapses in Major Depressive Disorder (MDD). Therefore, treatment approaches focusing on strategies to overcome rumination have been developed over the last decades, e.g., by improving emotion regulation. However, little is yet known about the specific mechanisms of action of psychotherapy between sessions, and in particular analyses of time-dependent changes are scarce. Therefore, we used ecological momentary assessment (EMA) to collect data related to psychotherapy and well-being twice a day during a mindfulness-based emotion regulation training (MBERT). To this end, 40 patients suffering from MDD participated in a block-randomized controlled trial, consisting of an eight-session MBERT and an active wait-list control. Results give further support to the effectiveness of mindfulness-based therapy in the treatment of MDD by showing its effects in ecologically valid circumstances: Throughout MBERT, subjective stress and rumination decreased, whereas self-efficacy, self-kindness, mindful distancing and sleep quality increased. While internal causes and social interactions initially had a strong impact on subjective stress and rumination, patients were less vulnerable to such triggers after receiving MBERT. Regarding the temporal dynamics of these changes, self-efficacy, self-kindness and mindful distancing reciprocally enhanced each other, followed by a reduction in stress later on. The robustness and implications of the results are discussed.