Internet-Delivered Cognitive Behavioural Therapy for Major Depression and Anxiety Disorders: A Health Technology Assessment.

Background: Major depression is defined as a period of depression lasting at least 2 weeks characterized by depressed mood, most of the day, nearly every day, and/or markedly diminished interest or pleasure in all, or almost all, activities. Anxiety disorders encompass a broad range of disorders in which people experience feelings of fear and excessive worry that interfere with normal day-to-day functioning.Cognitive behavioural therapy (CBT) is a form of evidence-based psychotherapy used to treat major depression and anxiety disorders. Internet-delivered CBT (iCBT) is structured, goal-oriented CBT delivered via the internet. It may be guided, in which the patient communicates with a regulated health care professional, or unguided, in which the patient is not supported by a regulated health care professional.

Methods: We conducted a health technology assessment, which included an evaluation of clinical benefit, value for money, and patient preferences and values related to the use of iCBT for the treatment of mild to moderate major depression or anxiety disorders. We performed a systematic review of the clinical and economic literature and conducted a grey literature search. We reported Grading of Recommendations Assessment, Development, and Evaluation (GRADE) ratings if sufficient information was provided. When other quality assessment tools were used by the systematic review authors in the included studies, these were reported. We assessed the risk of bias within the included reviews. We also developed decision-analytic models to compare the costs and benefits of unguided iCBT, guided iCBT, face-to-face CBT, and usual care over 1 year using a sequential approach. We further explored the lifetime and short-term cost-effectiveness of stepped-care models, including iCBT, compared with usual care. We calculated incremental cost-effectiveness ratios (ICERs) from the perspective of the Ontario Ministry of Health and Long-Term Care and estimated the 5-year budget impact of publicly funding iCBT for mild to moderate major depression or anxiety disorders in Ontario. To contextualize the potential value of iCBT as a treatment option for major depression or anxiety disorders, we spoke with people with these conditions.

Results: People who had undergone guided iCBT for mild to moderate major depression (standardized mean difference [SMD] = 0.83, 95% CI 0.59-1.07, GRADE moderate), generalized anxiety disorder (SMD = 0.84, 95% CI 0.45-1.23, GRADE low), panic disorder (small to very large effects, GRADE low), and social phobia (SMD = 0.85, 95% CI 0.66-1.05, GRADE moderate) showed a statistically significant improvement in symptoms compared with people on a waiting list. People who had undergone iCBT for panic disorder (SMD= 1.15, 95% CI: 0.94 to 1.37) and iCBT for social anxiety disorder (SMD=0.91, 95% CI: 0.74-1.07) showed a statistically significant improvement in symptoms compared with people on a waiting list. There was a statistically significant improvement in quality of life for people with generalized anxiety disorder who had undergone iCBT (SMD = 0.38, 95% CI 0.08-0.67) compared with people on a waiting list. The mean differences between people who had undergone iCBT compared with usual care at 3, 5, and 8 months were -4.3, -3.9, and -5.9, respectively. The negative mean difference at each follow-up showed an improvement in symptoms of depression for participants randomized to the iCBT group compared with usual care. People who had undergone guided iCBT showed no statistically significant improvement in symptoms of panic disorder compared with individual or group face-to-face CBT (d = 0.00, 95% CI -0.41 to 0.41, GRADE very low). Similarly, there was no statistically significant difference in symptoms of specific phobia in people who had undergone guided iCBT compared with brief therapist-led exposure (GRADE very low). There was a small statistically significant improvement in symptoms in favour of guided iCBT compared with group face-to-face CBT (d= 0.41, 95% CI 0.03-0.78, GRADE low) for social phobia. There was no statistically significant improvement in quality of life reported for people with panic disorder who had undergone iCBT compared with face-to-face CBT (SMD = -0.07, 95% CI -0.34 to 0.21).Guided iCBT was the optimal strategy in the reference case cost-utility analyses. For adults with mild to moderate major depression, guided iCBT was associated with increases in both quality-adjusted survival (0.04 quality-adjusted life-years [QALYs]) and cost ($1,257), yielding an ICER of $31,575 per QALY gained when compared with usual care. In adults with anxiety disorders, guided iCBT was also associated with increases in both quality-adjusted survival (0.03 QALYs) and cost ($1,395), yielding an ICER of $43,214 per QALY gained when compared with unguided iCBT. In this population, guided iCBT was associated with an ICER of $26,719 per QALY gained when compared with usual care. The probability of cost-effectiveness of guided iCBT for major depression and anxiety disorders, respectively, was 67% and 70% at willingness-to-pay of $100,000 per QALY gained. Guided iCBT delivered within stepped-care models appears to represent good value for money for the treatment of mild to moderate major depression and anxiety disorders.Assuming a 3% increase in access per year (from about 8,000 people in year 1 to about 32,000 people in year 5), the net budget impact of publicly funding guided iCBT for the treatment of mild to moderate major depression would range from about $10 million in year 1 to about $40 million in year 5. The corresponding net budget impact for the treatment of anxiety disorders would range from about $16 million in year 1 (about 13,000 people) to about $65 million in year 5 (about 52,000 people).People with depression or an anxiety disorder with whom we spoke reported that iCBT improves access for those who face challenges with face-to-face therapy because of costs, time, or the severity of their condition. They reported that iCBT provides better control over the pace, time, and location of therapy, as well as greater access to educational material. Some reported barriers to iCBT include the cost of therapy; the need for a computer and internet access, computer literacy, and the ability to understand complex written information. Language and disability barriers also exist. Reported limitations to iCBT include the ridigity of the program, the lack of face-to-face interactions with a therapist, technological difficulties, and the inability of an internet protocol to treat severe depression and some types of anxiety disorder.

Conclusions: Compared with waiting list, guided iCBT is effective and likely results in symptom improvement in mild to moderate major depression and social phobia. Guided iCBT may improve the symptoms of generalized anxiety disorder and panic disorder compared with waiting list. However, we are uncertain about the effectiveness of iCBT compared with individual or group face-to-face CBT. Guided iCBT represents good value for money and could be offered for the short-term treatment of adults with mild to moderate major depression or anxiety disorders. Most people with mild to moderate depression or anxiety disorders with whom we spoke felt that, despite some perceived limitations, iCBT provides greater control over the time, pace, and location of therapy. It also improves access for people who could not otherwise access therapy because of cost, time, or the nature of their health condition.