By using functional MRI to monitor areas of the brain that are activated or deactivated in response to emotional stimuli, a team at the University of Pittsburgh believes it can detect with reasonable accuracy those for whom it is worth pursuing cognitive behavioral therapy.
For others, reported Greg J. Siegle, Ph.D., and colleagues in the April issue of the American Journal of Psychiatry, cognitive behavioral therapy is a waste of time and resources, and can delay initiation of a different form of treatment.
In a study of unmedicated people with depression and never-depressed controls, those who were depressed and who showed low sustained reactivity in the subgenual cingulate cortex and high reactivity in the amygdala had the strongest benefit after 16 sessions of cognitive behavioral therapy, found the Pittsburgh team.
"These data could suggest that cognitive behavioral therapy is most useful to those who demonstrate increased emotional reactivity and who cannot engage regulatory structures," the authors wrote.
"Cognitive behavioral therapy may potentially help these individuals regain emotional control," they added. "Those who have neither sustained amygdala reactivity nor disrupted emotion regulation (especially subgenual cingulate cortex function) may not benefit as much from cognitive behavioral therapy."
The researchers used automatic sustained emotional reactivity (processing with rumination or elaboration, for example) as the target of their experiment. They did this because it is specifically addressed by cognitive behavioral therapy and because people who are depressed have been shown to display increased and sustained reactivity in brain regions involved with emotional processing, particularly the amygdala.
The investigators enrolled 14 patients (seven men) with depression and 21 never-depressed controls to undergo functional MRI (fMRI). All depressed patients were off medication for at least two weeks, or for at least six weeks for those who had been taking Prozac (fluoxetine).
During the scans, the participants were asked to rate as quickly and as accurately as possible the relevance to them of 60 emotional words by pushing buttons on a response box, according to whether each word was relevant, somewhat relevant, or not relevant. The emotional valences of the words were evenly divided into positive, neutral and negative.
Following the scans, the depressed participants underwent 16 sessions of cognitive behavioral therapy over 12 weeks, as part of a larger clinical trial. At each session severity of depressive symptoms were assessed with the Beck Inventory of Depression II.
The investigators found that compared with controls, nine of the participants with depression had low sustained reactivity in the subgenual cingulate cortex (Brodmann's area 25) after they read and rated negative words. Of this group, seven recovered from their depressive symptoms after cognitive behavioral therapy.
In contrast, of the five participants who had no fMRI evidence of decreased activity in the same region on the negative-word rating task, only one had remission of depressive symptoms after completing cognitive behavioral therapy.
The authors also found that increased activity in a region of the right amygdala was associated with improved response to cognitive behavioral therapy above and beyond the initial severity of symptoms. Amygdala activity was only marginally predictive of recovery status, however.
The investigators acknowledged that the small size of the sample and the use of a hypothesis-guided task and analysis could limit the value of the results, and might result in an underestimation of the predictive power of functional imaging or emotional processing.
"Upon larger replications, imaging of emotional information processing could aid in recommending cognitive behavioral therapy to individuals for whom it appears most appropriate or for recommending other interventions to individuals for whom benefit is less strongly predicted," they concluded.
- Reviewed by Robert Jasmer, MD Assistant Professor of Medicine, University of California, San Francisco
American Journal of PsychiatrySource Reference: Siegle GJ. "Use of fMRI to Predict Recovery From Unipolar Depression With Cognitive Behavior Therapy" Am J Psychiatry 2006; 163:735-738