This study provides very strong evidence for the value of Mindfulness-Based Cognitive Therapy (MBCT) as a treatment option for people with depression who have not improved after receiving intensive psychological treatments within the NHS. Compared to treatment as usual, adding MBCT - delivered in a group and by video call - achieved a greater reduction in depressive symptoms, with benefits sustained up to six months later. Improvements in participants' work and social functioning were also observed.

A particularly relevant finding is that this intervention, validated in a group and online format, proves to be effective even in people with complex clinical conditions: many of the participants had a history of depression from an early age, several relapses, comorbidities and were on medication. The fact that MBCT works in this context suggests that it can be an effective and safe alternative in cases of difficult-to-treat depression, and not only as an add-on, but also as a possible next step when other approaches have failed.

Validating this approach in an online and group format is an important step forward, as it considerably improves its scalability: it allows it to be offered to more people, at lower cost and without the need for travel, which is key to broadening access to evidence-based psychological treatments.

Furthermore, from a health perspective, MBCT showed good cost-effectiveness: not only was it clinically more effective, but it also reduced costs in health and social services, even considering the resources needed for its implementation. This evidence, together with previous studies, supports its inclusion in clinical guidelines as a second- or third-line treatment.

In Spain, MBCT has also been shown to be feasible and safe in primary care (Elices et al., 2022). Although it does not replace conventional treatments, it represents a promising, accessible and scalable tool that can expand therapeutic options in the public health system.

The study published in The Lancet Psychiatry represents a major advance in the treatment of resistant depression. Mindfulness-based cognitive therapy (MBCT) showed higher effectiveness compared to treatment as usual, even in patients who had not remitted after previous intensive interventions. The study methodology is robust, with a randomised, controlled design and 34-week follow-up, which supports the robustness of its conclusions.

This work provides conclusive evidence that MBCT can be an effective and cost-effective second-line treatment option in structured clinical settings. Although direct extrapolation to other health systems, such as the Spanish one, should be done with caution and requires further research, the model is scalable and compatible with primary mental health care. Its implementation could lead to a substantial improvement in the continuity of care for cases of difficult-to-treat depression.