The odds that a person who suffers from severe, nonchronic depression will recover are improved by as much as 30 percent if they are treated with a combination of cognitive therapy and antidepressant medicine rather than by antidepressants alone. However, a person with chronic or less severe depression does not receive the same additional benefit from combining the two.
That is the result of a major new clinical trial published online by the journal JAMA Psychiatry on Aug. 20.
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, the Gertrude Conaway Professor of Psychology at Vanderbilt University, 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 United States in treatment of depression. The use of combined cognitive therapy and antidepressive medicine is standard for severe cases in the UK, and the English National Health Service is actively training its therapists in cognitive therapy and other empirically supported psychotherapies.
Collaborators in the study were Robert DeRubeis and Jay Amsterdam from the University of Pennsylvania; Jan Fawcett from the University of New Mexico, Albuquerque; Richard Shelton from the University of Alabama, Birmingham; John Zajecka and Paula Young from Rush University; and Robert Gallop from West Chester University.
The study was supported by grants MH60713, MH01697, MH60998 and MH060768 from the National Institute of Mental Health.