Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: A randomised controlled trial

To examine the efficacy of transdiagnostic internet-delivered cognitive behavioural therapy (iCBT), mindfulness-enhanced iCBT, and stand-alone online mindfulness training compared with a usual care control group (TAU) for clinical anxiety and depression. Individuals (N = 158) with a DSM-5 diagnosis of a depressive and/or anxiety disorder were randomised to one of the three clinician-guided online interventions, or TAU over a 14-week intervention period. The primary outcomes were self-reported depression (PHQ-9) and anxiety (GAD-7) severity at post-treatment. Secondary outcomes included adherence rates, functional impairment (WHODAS-II), general distress (K−10), and diagnostic status at the 3-month follow-up (intervention groups). All three programs achieved significant and large reductions in symptoms of depression (g = 0.89–1.53), anxiety (g = 1.04–1.40), and distress (g = 1.25–1.76); and medium to large reductions in functional impairment (g = 0.53–0.98) from baseline to post-treatment and 3-month follow-up. Intention-to-treat linear mixed models showed that all three online programs were superior to usual care at reducing symptoms of depression (g = 0.89–1.18) and anxiety (g = 1.00–1.23). Transdiagnostic iCBT, mindfulness-enhanced iCBT and online mindfulness training are more efficacious for treating depression and anxiety disorders than usual care, and represent an accessible treatment option for these disorders. •Recruited participants with DSM-5 anxiety disorders and/or depression•Compared internet CBT, mindfulness-enhanced CBT, and mindfulness training with TAU•Reductions in anxiety, depression, distress and functional impairment were observed.•All three clinician-guided online programs were more efficacious than usual care.