The role of cognitive and affective changes in preventing depressive relapse: A network analysis approach to understanding the mechanisms of preventive cognitive therapy

BACKGROUND: Relapse is a debilitating and common feature of Major Depressive Disorder (MDD). Preventive cognitive therapy (PCT), designed for relapse prevention and delivered after remission, has been shown clinically effective in preventing relapse up to 20 years, but mechanisms are currently unclear. A comprehensive understanding of the cognitive-affective processes that change after PCT may point to intervention targets that are essential in lowering the relapse risk further. METHODS: Using data from 69 unmedicated remitted recurrent MDD individuals in the NEWPRIDE randomized controlled trial, we examined changes in cognitive and affective process following a three-month PCT intervention (n = 45) or waiting list (n = 24). We investigated changes in cognitive and affective domains of functioning using a mixed graphical model and studied which changes predicted relapse at 18 months. RESULTS: PCT related directly to changes in anhedonia and habitual use of cognitive reappraisal, which were in turn related to changes in dysfunctional attitudes. Anhedonia was identified as a mediator in lowering dysfunctional attitudes in PCT recipients, (a2b2: est. = 0.361, p = 0.003). Finally, change in anhedonia [OR = 0.79; 95% CI:0.68-0.92, p = 0.003] and dysfunctional attitudes [OR = 0.93; 95% CI: 0.86-0.99, p = 0.041] predicted relapse status at 18-month follow-up in PCT-recipients. CONCLUSIONS: Our findings suggest that changes in anhedonia and dysfunctional attitudes explain the long-term relapse preventive effects of PCT, of which the latter is partially achieved through effects on anhedonia. This suggests that modulating the positive affective domain is a crucial aspect of PCT in lowering the dysfunctional attitudes vulnerability for relapse.