However, researchers discovered a person with chronic or less severe depression does not receive the same additional benefit from combining the two.
Investigators found the odds that a person who suffers from severe, non-chronic depression will recover are improved by as much as 30 percent if they are treated with the combined approach.
The study is published online by the journal JAMA Psychiatry.
In North America, about one in five women and one in 10 men suffer from major depression in her or his lifetime.
“Our results indicate that combining cognitive therapy with antidepressant medicine can make a much bigger difference than we had thought to about one-third of patients suffering from major depressive disorder,” said Steven Hollon, Ph.D., who directed the study.
“On the other hand, it does not appear to provide any additional benefit for the other two-thirds.”
Previous studies have found that about two-thirds of all patients with major depressive disorder will improve on antidepressant medications and about one-third of patients will achieve full remission, but half then relapse before fully recovering.
Cognitive therapy has proven to be about as effective as medication alone but its effects tend to be longer lasting. Combining the two has been estimated to improve recovery rates by 6 to 33 percent.
“Now, we have to reconsider our general rule of thumb that combining the two treatments keeps the benefits of both,” said Hollon.
The new study was a randomized clinical trial involving 452 adult outpatients with chronic or recurrent major depressive disorder.
Unlike previous studies that followed subjects for a set period of time, this study treated them for as long as it took first to remission (full normalization of symptoms) and then to recovery (six months without relapse), which in some cases took as long as three years.
“This provided us with enough data so that we could drill down and see how the combined treatment was working for patients with different types and severity of depression: chronic, recurrent, severe and moderate,” Hollon said.
According to the psychologist, the results could have a major impact on how major depressive disorder is treated.
The most immediate effect is likely to be in the United Kingdom, which, he said, is 10 years ahead of the U.S. in treatment of depression.
The use of combined cognitive therapy and antidepressant medication is standard for severe cases in the UK, although it is less usually recommended in the United States. The UK’s English National Health Service is actively training its therapists in cognitive therapy and other empirically supported psychotherapies.
Source: Vanderbilt University