The study found when CBT was given, in addition to usual care that included antidepressants, it was effective in reducing depressive symptoms and improving quality of life over the long term – on average 46 months – for patients whose depression had not responded to medication. These benefits were found, on average, 40 months after the end of therapy.
Over the course of 46 months, 43 per cent of those who had received CBT had improved, reporting at least a 50 per cent reduction in symptoms of depression, compared with 27 per cent who continued with their usual care alone. Importantly, the study also found that this type of ‘high intensity’ CBT was a cost effective treatment from the perspective of the health service.
A psychological treatment that teaches people skills for life needs to show enduring effects. It is really important therefore that this study shows that for people with largely longstanding, complex depression, CBT leads to enduring effects over four years compared with usual care in the NHS. This is a key finding with one of the longest follow-ups of a large scale trial to date. - Dr Willem Kuyken, Director of the Oxford Mindfulness Centre and Professor of Clinical Psychology at the University of Oxford's Department of Psychiatry
The research was conducted by academics at the University of Bristol, along with colleagues from the Universities of Exeter, Oxford, Glasgow, and University College London.
The paper, ‘Long-term effectiveness and cost-effectiveness of cognitive behavioural therapy as an adjunct to pharmacotherapy for treatment resistant depression in primary care: follow-up of the CoBalT trial’ was published in The Lancet Psychiatry.
The research was funded by the National Institute for Health Research Health Technology Assessment (NIHR HTA).
Read the full paper published in The Lancet Psychiatry here.