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CBT plus antidepressants has long-term clinical, cost-effectiveness for treatment-resistant depression

Results from long-term follow-up of the CoBalT randomized controlled trial indicated clinical and cost-effectiveness of cognitive behavioral therapy in addition to usual care that included antidepressants for individuals with treatment-resistant depression.

“Cognitive behavioral therapy (CBT) is an effective treatment for depression, including for those who have not responded to antidepressants … However, little evidence of long-term effectiveness exists,” the researchers wrote. “Many trials report outcomes at the end of therapy and although there is evidence that CBT is effective and cost effective in the medium term (6 to 12 months), many of these trials are small with sample sizes of fewer than 75 participants per group.”

In long-term follow-up of the CoBalT trial, researchers assessed clinical and cost-effectiveness of CBT plus usual care that included medication among primary care patients with treatment-resistant depression over 3 to 5 years. Study participants, aged 18 to 75 years, who adhered to antidepressants for at least 6 weeks were randomly assigned to usual care or CBT in addition to usual care. Median follow-up was 45.5 months and included 248 original study participants.

At follow-up, participants in the intervention group had a mean Beck Depression Inventory (BDI-II) score of 19.2, compared with a mean BDI-II score of 23.4 among those in the usual care group.

Repeated measures analysis over 46 months indicated a difference in mean BDI-II scores of –4.7 (95% CI, –6.4 to –3; P < .001).

The average annual cost of trial CBT per participant was £343, with an incremental cost-effectiveness ratio of £5,374 per quality-adjusted life-year gain. This represented a 92% probability of cost-effectiveness at the National Institute for Health and Care Excellence quality-adjusted life-year threshold of £20,000, according to researchers.

“To our knowledge, this study is the first to show long-term effectiveness of CBT as an adjunct to pharmacotherapy for primary care patients with treatment-resistant depression,” the researchers wrote. “Present findings represent the first evidence of long-term cost-effectiveness. The cost difference between groups was driven by the initial cost of therapy, as health care costs were very similar for the duration and no top-up sessions were offered. The benefit, in terms of health-related quality of life, was sustained over time, and therefore achieved at no additional cost. This finding reinforces our conclusion at 12 months that investing in CBT services for these patients represents an efficient use of healthcare resources.” – by Amanda Oldt

Disclosure: Wiles reports no relevant financial disclosures. Please see the full study for a list of all authors’ relevant financial disclosures.