Depression does not always lift with standard treatment. For a significant number of people, it continues despite trying antidepressants and other approaches, sometimes for years. This is often called chronic or treatment-resistant depression, and it presents a real challenge for mental health care.
A pragmatic randomised controlled trial by Cladder-Micus and colleagues set out to examine mindfulness-based cognitive therapy (MBCT) in exactly this group. MBCT is a structured program that combines mindfulness practice with elements of cognitive behavioural therapy. It has already been shown to help people who are currently depressed or in remission from depression. What has not been clear is whether it can help when depression has become chronic and has not responded to other treatments.
That is the gap this trial was designed to address. Rather than testing MBCT in a general depressed population, the researchers focused specifically on patients whose depression had proven resistant to treatment, and compared outcomes under everyday clinical conditions.
Treatment resistance can leave people feeling as though they have exhausted their options. Research of this kind matters because it asks, carefully and systematically, whether a different kind of approach, one focused on how a person relates to their thoughts rather than on changing the thoughts themselves, has anything to offer.
If depression has stayed with you despite previous treatment, it can be worth speaking with a psychologist about what other options exist.
What the study did
Cladder-Micus et al. ran a pragmatic, multicenter randomized-controlled trial (RCT) — a study design where participants are randomly assigned to different treatments so that any differences in outcomes can be attributed to the treatment itself rather than other factors. "Pragmatic" means the trial was designed to reflect real-world clinical conditions rather than a tightly controlled lab setting.
The 106 participants all had chronic depression that had already resisted treatment: everyone had previously received at least 4 weeks of pharmacotherapy (medication) and at least 10 sessions of psychological treatment. They were randomly assigned to either treatment-as-usual (TAU) alone, or mindfulness-based cognitive therapy (MBCT) added on top of TAU. MBCT combines mindfulness meditation practices with cognitive-behavioural techniques, and is usually taught in a structured group program.
The researchers used two ways of analysing the results. An intention-to-treat (ITT) analysis includes everyone who was randomised, whether or not they actually completed treatment — this gives a realistic picture of what happens when a treatment is offered. A per-protocol analysis only includes people who actually finished the program, showing what happens when the treatment is properly received.
What it found
In the ITT analysis, the MBCT + TAU group did not show a statistically significant reduction in depressive symptoms compared with TAU alone (difference of -3.23 points, effect size d = 0.35, p = 0.09). An effect size like Cohen's d expresses how large a difference is in standardised terms — 0.35 would generally be considered a small-to-moderate effect, but here it did not reach the conventional threshold for statistical significance (p < 0.05).
However, several other outcomes did favour MBCT + TAU significantly: higher remission rates (a statistical test called chi-square, χ²(2) = 4.25, p = 0.04), lower rumination — the tendency to repetitively dwell on negative thoughts (d = 0.39, p = 0.04) — higher quality of life (d = 0.42, p = 0.048), and greater gains in mindfulness skills (d = 0.73, p < 0.001) and self-compassion (d = 0.64, p = 0.001).
Notably, 24.5% of people assigned to MBCT (12 people) did not complete it. When the researchers looked only at those who did complete MBCT (the per-protocol analysis), depressive symptoms were significantly lower than in the TAU group (d = 0.45, p = 0.04).
Why it matters
This is a nuanced but genuinely useful result. The overall, real-world (ITT) effect on depressive symptoms wasn't statistically significant — an honest and important finding in itself. But people who completed MBCT showed meaningful symptom reduction, and across the whole group, MBCT led to better remission, less rumination, better quality of life, and stronger mindfulness and self-compassion skills. For a population often considered very hard to help, that's meaningful.
Its limits
The dropout rate in the MBCT group was notable, and the authors themselves flag that the reasons for non-completion need further investigation. This study also doesn't tell us why MBCT helps some people more than others, or how it compares to other active treatments beyond usual care.
If you've tried treatment before and are still struggling, please don't assume nothing will help — it's worth speaking with a psychologist about your options.