Mechanisms of change in the treatment of major depressive disorder with metacognitive therapy and behavioral activation - a random intercept cross-lagged panel and mediation analyses.

OBJECTIVES

Metacognitive Therapy (MCT) and Behavioural Activation (BA) are effective treatments for depression. This exploratory study aimed to investigate proposed mechanisms and mediators of change in MCT and BA.

METHOD: Data were used from 122 patients randomized to six months of treatment with either MCT or BA for depression. Analyses were based on monthly assessments of the Quick Inventory of Depressive Symptoms (QIDS-SR16), Major Depressive Disorder Scale (MDD-S, for MCT-specific variables), and Behavioral Activation for Depression Scale (BADS, for BA-specific variables).

RESULTS

Random intercept cross-lagged panel models (RI-CLPMs) indicated bidirectional relationships between most of the proposed mechanism variables and outcomes. Linear mixed models revealed greater changes in the MDD-S variables rumination time, dysfunctional coping strategies, and negative metacognitions in the MCT condition. RI-CLPM mediation analyses suggested that the subscales avoidance, rumination time, and negative metacognitions of the MDD-S mediate the relationship between treatment condition and depressive symptoms.

CONCLUSION

Our results suggest that the examined variables are change mechanisms in the treatment of depression. They also suggest that the effect of MCT might be mediated by changes in rumination. If confirmed in further studies, it might emerge that targeting these change mechanisms can increase the effectiveness of depression treatments.