What is the clinical effectiveness of internet-delivered cognitive behavioural therapy for patients with mild to moderate major depression or anxiety disorders?
Nine randomized controlled trials were identified regarding the clinical effectiveness of iCBT for patients with mild to moderate major depression or anxiety disorders. The studies were heterogeneous with respect to features of the iCBT programs (e.g., number of modules, duration, level of guidance, and frequency of support) and the scales used to assess patient outcomes.Two randomized controlled trials included patients with mild to moderate major depression. One trial concluded that iCBT was non-inferior to care as usual, while the second study concluded that both unguided and therapist-guided iCBT conferred a benefit over improved treatment as usual at 6- and 15-month follow-up assessments. The authors of the second study reported that there were no significant differences between unguided iCBT and therapist-guided iCBT at any time in the trial.One randomized controlled trial included patients with social anxiety disorder. Patients were randomized to wait list control or iCBT delivered using either a computer or a smartphone. The authors concluded that either mode of delivery offered benefits to patients in the form of symptom reduction compared to the wait list group.Six randomized controlled trials included mixed patient populations with major depression, social anxiety disorder, generalized anxiety disorder, panic disorder with or without agoraphobia, or any combination of these. Five of these studies found iCBT to be more effective than care as usual or wait list control for reducing depression or anxiety symptoms. The sixth study did not assess symptom severity, but it did report a high degree satisfaction with care in patients treated with iCBT.Overall, the evidence base suggested that iCBT interventions are effective for mild to moderate major depression, generalized anxiety disorder, panic disorder with or without agoraphobia, and social anxiety disorder compared to wait list control, treatment as usual, or improved treatment as usual. However, the included studies from which these findings were summarized from have significant limitations that are detailed within this report. Due to the supplementary nature of this report, the evidence summarized here should not be interpreted without also considering the analysis conducted in the HQO and CADTH collaborative project entitled Internet-Delivered Cognitive Behavioural Therapy for Major Depressive Disorder and Anxiety Disorders: A Health Technology Assessment.