Computerized cognitive–behavioural therapy (cCBT) forms a core component of stepped psychological care for depression. Existing evidence for cCBT has been informed by developer-led trials. This is the first study based on a large independent pragmatic trial to assess the cost-effectiveness of cCBT as an adjunct to usual general practitioner (GP) care compared with usual GP care alone and to establish the differential cost-effectiveness of a free-to-use cCBT programme (MoodGYM) in comparison with a commercial programme (Beating the Blues) in primary care.

Costs were estimated from a healthcare perspective and outcomes measured using quality-adjusted life years (QALYs) over 2 years. The incremental cost-effectiveness of each cCBT programme was compared with usual GP care. Uncertainty was estimated using probabilistic sensitivity analysis and scenario analyses were performed to assess the robustness of results.

Neither cCBT programme was found to be cost-effective compared with usual GP care alone. At a £20 000 per QALY threshold, usual GP care alone had the highest probability of being cost-effective (0.55) followed by MoodGYM (0.42) and Beating the Blues (0.04). Usual GP care alone was also the cost-effective intervention in the majority of scenario analyses. However, the magnitude of the differences in costs and QALYs between all groups appeared minor (and non-significant).

Technically supported cCBT programmes do not appear any more cost-effective than usual GP care alone. No cost-effective advantage of the commercially developed cCBT programme was evident compared with the free-to-use cCBT programme. Current UK practice recommendations for cCBT may need to be reconsidered in the light of the results.