Antidepressants are the most widely used treatment for people with moderate to severe depression but up to two thirds of people with depression don't respond fully to antidepressants.

A new paper in The Lancet says cognitive behavioral therapy reduces symptoms of depression and helps improve patient quality of life when provided in addition to the usual care.

They say this is the first large-scale trial to test the effectiveness of cognitive behavioral therapy, a type of talking psychotherapy, given in addition to usual care that includes antidepressants. The CoBalT study aimed to determine the best 'next step' treatment for people whose depression had not responded to medication alone. 

The CoBaIT team, comprising researchers from the Universities of Bristol, Exeter and Glasgow, recruited 469 patients aged 18- to 75-years with treatment-resistant depression for the randomized controlled trial. Patients were split into two groups - 235 patients continued with their usual care, which included continuing on antidepressant medication, and 234 patients were treated with cognitive behavioral therapy in addition to their usual care. Researchers followed-up with 422 patients (90%) at six months and 396 (84%) at 12 months to compare their progress.  

At six months, 46% of those who received cognitive behavioral therapy in addition to usual care had improved, reporting at least a 50 per cent reduction in symptoms of depression, compared to 22 per cent of those who continued with usual care alone. This beneficial effect was maintained over 12 months.

They conclude that the findings demonstrate that cognitive behavioral therapy provided in addition to usual care including antidepressant medication is an effective treatment that reduces depressive symptoms, and improves the quality of life in patients whose depression has not responded to the most common first-line treatment for depression in primary care.

Dr. Nicola Wiles, the study's lead author and a Senior Lecturer in the University of Bristol's School of Social and Community Medicine, said, "Antidepressants are often the first-line treatment for depression — a major public health problem with the World Health Organisation estimating that over 300 million people are affected globally. However, in many countries, access to psychological treatments such as CBT is limited to people who can afford to pay, or those with health insurance. These findings emphasise the importance of increasing the availability of psychological therapy. While there have been initiatives to increase access to such treatments in both the UK and Australia, worldwide initiatives are rare, and even in the UK many people who have not responded to antidepressants do not get psychological treatment. Our study suggests that by investing in psychological services it is possible to reduce the significant burden to patients and healthcare systems that is associated with non-response to antidepressant medication.

"Furthermore, it is important to acknowledge that while we found CBT was an effective treatment for this patient group, not everyone who received CBT improved. It is therefore essential that we invest in further research in this area to investigate alternative treatment options, both pharmacological and non-pharmacological, for the significant number of patients whose depression does not get better following treatment with antidepressants."

Willem Kuyken, Professor of Clinical Psychology at the University of Exeter, added, "This trial provides further evidence that psychological treatments like cognitive therapy can provide substantive and lasting help to people who suffer depression. The Mood Disorders Centre, one of the participating sites, aims to make evidence-based psychological approaches as accessible as possible to people suffering depression. This trial demonstrates that people with complex and longstanding needs who have not responded to antidepressants can derive substantive and lasting benefit from CBT delivered by well trained therapists. Showing that 40 per cent of people who had been in cognitive therapy were largely free of symptoms at 12 months is really important because it bodes well for their longer-term recovery." 

John Campbell, Professor of General Practice at the University of Exeter Medical School, stated, "Depression is a very common illness, encountered frequently by GPs and their patients. While drug treatments can be very effective, not all patients will respond well to treatment. For some patients, the experience of depression can be particularly difficult. We were delighted that so many patients, GPs, and practices helped us with this research. The results we present today show that for some patients, the addition of a 'talking therapy' such as CBT can be very effective in treating the depression and helping resolve disabling symptoms. GPs and their patients can take real encouragement from these findings which provide real support for the use of CBT in patients where other treatments may have failed."

Chris Williams, Professor of Psychosocial Psychiatry at the University of Glasgow, added, "This research is also of great importance because it used a CBT intervention alongside treatment with antidepressants. It confirms how these approaches — the psychological and physical — treatments can complement each other. It was also encouraging because we found the approach worked to good effect across a wide range of people of different ages and living in a variety of settings."