CBT is a well-established treatment for depression, especially for people who don’t respond to medication alone. But researchers haven’t fully understood what drives its effectiveness.
This new analysis of data from the CoBalT trial - a major UK study of CBT for treatment-resistant depression funded by the National Institute for Health and Care Research (NIHR) - found that mental health literacy (how well people understand and manage their mental health) plays a crucial role in how CBT works.
The researchers discovered that:
- 73% of the improvement in depression symptoms after CBT could be explained by increases in mental health literacy.
- When other psychological factors like negative thinking patterns and self-awareness were also considered, this figure rose to 77%.
- Even when early improvements in symptoms were taken into account, mental health literacy still explained over half of the long-term benefit.
Dr Charlotte Archer, Research Fellow at the Centre for Academic Mental Health and Centre for Academic Primary Care at the University of Bristol, and lead author of the study, said: "CBT teaches people to recognise and change unhelpful thoughts and behaviours. Our findings suggest that when people better understand their mental health, they’re more likely to apply what they’ve learned, and that’s what leads to lasting change."
The study highlights the importance of mental health education as part of therapy and suggests that boosting mental health literacy could make treatments like CBT even more effective.
How the study was conducted
The study used a statistical method called mediation analysis to understand how cognitive behavioural therapy (CBT) helps people with depression - specifically, whether improvements in mental health literacy explain some of the benefits of CBT.
Using data from a large University of Bristol led UK trial called CoBalT, which looked at how effective CBT is for people whose depression hadn’t improved with medication alone, the researchers looked at three things:
- How well people understood and managed their mental health (called perceived mental health literacy).
- Their patterns of negative thinking (dysfunctional attitudes).
- Their ability to step back and observe their thoughts (metacognitive awareness).
They measured these factors at 6 months and then looked at how depressed people felt at 12 months.
Using statistical models, they tested whether improvements in mental health literacy explained the reduction in depression symptoms. They found that mental health literacy explained a large part of the improvement, even more than the other psychological factors they looked at.
Paper: Perceived mental health literacy as a mediator between cognitive behavioural therapy (CBT) and depressive symptoms: a secondary data analysis of CoBalT trial data by Charlotte Archer, Gemma Hammerton, David Kessler, John Campbell, Willem Kuyken, Gemma Lewis, Glyn Lewis, Chris Williams and Nicola Wiles. Published in Cognitive Behaviour Therapy. September 2025.