Major depressive disorder does not improve adequately for many patients after medication or psychological treatment. About one-third continue to experience clinically important symptoms despite standard care. This group is increasingly described as having difficult-to-treat depression, which can include treatment non-response, failure to reach remission, treatment resistance, or a chronic course. These patients often have long illness histories, recurrent episodes, and co-occurring mental health conditions.
Mindfulness-Based Cognitive Therapy (MBCT) combines mindfulness meditation with elements of cognitive therapy. The program is intended to help people recognize repetitive negative thinking and respond to difficult thoughts and emotions in less automatic ways. MBCT is recommended for preventing depressive relapse, but evidence concerning its use as a treatment for a current and persistent depressive episode has been distributed across small individual trials.
Barnhofer et al. [Psychotherapy and Psychosomatics] conducted a systematic review and individual participant data meta-analysis to examine the effects of MBCT in adults with difficult-to-treat depression. Unlike a conventional meta-analysis based only on published group averages, the researchers obtained participant-level data from the original trials. This allowed outcomes to be analyzed using a common approach and potential differences in treatment response across patient groups to be examined.
The analysis included seven randomized controlled trials involving 777 adults. Their average age was 46 years, and 70% were women. Among participants with available clinical data, 66% had chronic depression, 57% had a comorbid anxiety disorder, and approximately 80% were taking antidepressant medication. Five studies delivered MBCT face-to-face and two used videoconferencing. Six studies compared MBCT with treatment as usual, three compared it with an active psychosocial intervention, and two included both types of comparison groups.
The original studies used several self-report and clinician-rated depression measures. The researchers converted scores into a common metric and evaluated depressive symptom severity at post-treatment and medium-term follow-up. They also estimated rates of remission, clinically meaningful improvement, and reliable symptom deterioration.
The results showed that MBCT reduced depressive symptoms more than treatment as usual at post-treatment, with a small-to-moderate standardized mean difference of −0.40 (95% credible interval [CrI]: −0.65 to −0.16). A similar effect remained at medium-term follow-up (standardized mean difference = −0.41; 95% CrI: −0.76 to −0.03).
The estimated probability that the effect exceeded the study’s tentative threshold for clinical relevance was 92% at post-treatment and 85% at medium-term follow-up. At post-treatment, the estimated remission rate was 30.9% with MBCT compared with 19.2% with treatment as usual. Clinically meaningful improvement occurred in 40.6% of MBCT participants compared with 19.3% of controls. Reliable symptom deterioration was uncommon in both conditions.
MBCT did not outperform other active psychosocial interventions. At post-treatment, the mean difference was 0.01 (95% CrI: −0.56 to 0.63), indicating considerable uncertainty and no evidence of superiority. The researchers also found no robust evidence that MBCT effects differed according to depression severity, chronicity, treatment resistance, comorbid anxiety, antidepressant use, or delivery through videoconference rather than in person.
Reference:
Barnhofer, T., Niemi, M., Michalak, J., ... Harrer, M. (2026). Efficacy and Moderators of Mindfulness-Based Cognitive Therapy in Difficult-to-Treat Depression: A Systematic Review and Individual Participant Data Meta-Analysis. Psychotherapy and Psychosomatics.
Link to study
