THURSDAY, Dec. 6 (HealthDay News) -- People suffering from depression who don't respond to antidepressants alone may find relief if they also undergo cognitive behavioral therapy, a new British study suggests.

Many of the two-thirds of those with depression who do not respond fully to antidepressants are three times more likely to improve with cognitive behavioral therapy, the researchers report.

"When people with depression have not responded to treatment with antidepressants, receiving cognitive behavioral therapy in addition to continuing on medication as part of usual care, reduces depressive symptoms and improves quality of life," said lead researcher Nicola Wiles, a senior lecturer in epidemiology at the University of Bristol.

The finding emphasizes the importance of investing more in psychological services, she said.

"In many countries, access to cognitive behavioral therapy is limited to those who can afford it. Even in the U.K., where there has been substantial investment in psychological services, many people who have not responded to antidepressants still do not receive more intensive psychological therapies such as cognitive behavioral therapy that takes 12 to 18 sessions," Wiles said.

"By investing in psychological services, it is possible to reduce the significant burden to patients that is associated with non-response to the most common treatment for depression," she added.

According to the National Association of Cognitive-Behavioral Therapists, cognitive behavioral therapy, unlike other so-called talk therapy, "is based on the idea that our thoughts cause our feelings and behaviors, not external things, like people, situations and events. The benefit of this fact is that we can change the way we think to feel and act better even if the situation does not change."

The report was published online Dec. 7 in The Lancet.

To test the value of cognitive behavioral therapy, Wiles' team randomly assigned more than 400 people who suffered from depression and who had not responded to six weeks of antidepressant therapy to continue their medications, some while receiving cognitive behavioral therapy and others not.

After six months, the researchers found that 46 percent of those receiving cognitive behavioral therapy improved, compared with 22 percent of those on antidepressants alone.

Improvement was pegged at a minimum 50 percent reduction in depressive symptoms, the researchers noted.

People receiving cognitive behavioral therapy were also more likely to not have any symptoms of depression or anxiety. And the results held a year later, the researchers added.

In Britain, about 3 percent of adults report being depressed. In the United States, about 7 percent of adults suffer from depression, the researchers noted.

By 2030, depression is expected to be the leading cause on disability in high-income countries, they added.

"An inadequate treatment response to antidepressant medication is an all-too-frequent outcome for depressed patients," said Michael Otto, a professor of psychology at Boston University and co-author of an accompanying journal editorial.

This study addresses this issue by showing that cognitive behavioral therapy is an useful next step for these patients, he said.

"Patients have a choice about treatment, either when initiating care or when trying to improve treatment response if the first option does not work," Otto said. "Cognitive behavioral therapy should figure highly in these treatment choices."

Simon Rego, director of psychology training at Montefiore Medical Center/Albert Einstein College of Medicine in New York City, said "there is a great deal of evidence that supports cognitive behavioral therapy as a first-line treatment for depression, it is often also suggested as a next-step treatment option for patients in primary care who have not responded to their antidepressants."

"This study adds to the already large evidence base in support of cognitive behavioral therapy for the treatment of depression," Rego said. "These results should provide hope to a wide range of depressed patients who are initially prescribed an antidepressant but fail to respond fully to it."

More information

For more on depression, visit the U.S. National Institute of Mental Health.