Mechanisms of change in long-term transdiagnostic cognitive behavioural therapy: the sequential effect of rumination and worry on symptoms and quality of life

Cogn Behav Ther. 2025 Oct 14:1-15. doi: 10.1080/16506073.2025.2573199. Online ahead of print.

ABSTRACT

Anxiety and depressive disorders are the most prevalent disorders worldwide and significantly impair quality of life (QoL). Transdiagnostic cognitive behavioural therapy (TD-CBT) is effective in treating these disorders and improving QoL, but its long-term mechanisms of change are poorly understood. Rumination and worry are key processes addressed by TD-CBT. In this study, we analysed the sequential effect of TD-CBT on post-treatment rumination and worry, anxiety/depression symptoms at 6-months and psychological and physical QoL at 12-months. We use data from PsicAP, a randomised clinical trial in the Primary Care (PC) setting, with 1061 participants randomised to TAU (treatment as usual) or TD-CBT+TAU. Path analyses using SEM were employed to test serial mediation models. Analyses indicated that TD-CBT exerts its long-term beneficial effects on QoL through a cascade of effects, whereby first the maladaptive cognitive processes of rumination and worry are reduced (post-treatment), then anxiety and depressive symptoms (6-months) and finally QoL is improved (12-months). This study provides longitudinal evidence on the mechanisms of change of TD-CBT in patients with anxiety and depression. It also highlights the importance of targeting transdiagnostic interventions towards early modification of negative repetitive thought processes as a critical pathway to long-term symptomatic and functional recovery.

PMID:41085966 | DOI:10.1080/16506073.2025.2573199