An Internet-Delivered Rumination-Focused CBT Intervention for Adults With Depression and Anxiety: A Randomized Controlled Trial.

Targeting transdiagnostic psychopathological mechanisms like repetitive negative thinking (RNT; worry, rumination) could improve interventions for depression and anxiety. The goal of the current study was to test whether therapist-supported internet-based RNT-targeting cognitive behavioral therapy reduces RNT, anxiety, and depression in adults with elevated RNT and anxiety and/or depression. To this end, a single-blind, two-arm parallel-group superiority randomized controlled trial (RCT) was conducted with 118 adults across Romania with elevated levels of worry and/or rumination and at least a subclinical/clinical diagnosis of major depressive disorder (MDD), dysthymia, generalized anxiety disorder (GAD), social anxiety disorder (SAD), or panic disorder. Eligible participants were randomized to internet rumination-focused CBT (i-RF-CBT; n = 59) or a waitlist control group (i-RF-CBT delayed 7 weeks; n = 59). Primary outcome was changes in perseverative thinking, anxiety, and depression 7 weeks after randomization. Secondary outcomes included changes on all measures after 6 months in the i-RF-CBT condition only. Participants in the i-RF-CBT arm showed significantly lower levels of perseverative thought [PTQ] (d = 0.44, 95% CI [0.23, 0.64], p<.001), brooding (d = 0.56, 95% CI [0.35, 0.77], p < .001), worry [PSWQ] (d = 0.62; 95% CI [0.40, 0.84], p < .001), anxiety [GAD7] (d = 0.41; 95% CI [0.21, 0.62], p < .001), and depression [PHQ9] (d = 0.38; 95% CI [0.18, 0.58], p < .001) after 7 weeks, relative to waitlist control. Improvements were maintained at the 6-month follow-up. The results showed that i-RF-CBT significantly reduced RNT, worry, rumination, anxiety, and depression in adults with anxiety and/or major depressive disorders, providing proof of principle that this approach can target RNT and that targeting RNT has transdiagnostic benefits on anxiety and depression symptoms.