In people with Post-Traumatic Stress Disorder (PTSD), certain brain activity patterns, in response to emotional cues, can predict who will benefit from exposure therapy, researchers report in a study published December 1, 2017, in The American Journal of Psychiatry.

Exposure therapy can be an effective treatment for PTSD, but works for only about half of patients. It involves gradually exposing someone greatly affected by severe stress to the things or situations that they fear –in a safe environment. This approach provides patients with a chance to reinterpret fearful triggers and has the effect of decreasing fear and avoidance. The new findings suggest that the success of such therapy may depend on the strength of brain networks underlying how an individual recognizes and processes frightening stimuli.

In the study, led by Amit Etkin, M.D., Ph.D., of Stanford University, a 2012 Young Investigator, 66 people with PTSD completed tasks requiring them to regulate their emotions. For example, one task involved ignoring emotions triggered by fearful faces and instead identifying the artificial tint of the picture. In another task, the participants were instructed to try to reduce their emotional response by interpreting a negative emotional scene differently.

As the participants completed the tasks, brain scans tracked how their brains responded to and dealt with the emotionally charged images. The participants were then randomly assigned to receive up to 12 sessions of exposure therapy or to join a waiting list for therapy. Those placed on the waiting list _were used as controls in the study.

Patients with the largest reductions in symptoms after treatment showed a particular activity pattern before the start of the treatment. In response to passively viewing fearful faces, they had less activation of a fear-processing brain area called the amygdala. They also showed greater activity in emotion-regulating regions in the prefrontal cortex.

These findings suggest that low reactivity to fearful cues and better ability to engage emotion-regulating brain areas are two factors that make an individual more likely to improve with therapy.

The same researchers conducted additional experiments, reported separately in The American Journal of Psychiatry. This research indicates that therapy also appears to actually change brain function in patients.

Four weeks after exposure therapy was completed, the researchers conducted a second brain scan to explore which brain networks are affected by therapy. The findings suggest therapy taps into brain networks that enable people to successfully reinterpret emotionally charged stimuli and change their emotional response.

During tasks that required deliberately reducing emotional response by differently interpreting fearful images, treated patients showed an increase in the activation of a brain area called the frontopolar cortex. Control participants who did not receive therapy did not show this increase.



These results suggest one of the key mechanisms by which therapy works is by improving the functioning of the frontopolar cortex, the researchers said.

Exposure therapy requires a considerable investment of time and effort, and these findings may help identify people who are most likely to benefit from it.

Dr. Etkin and his colleagues suggest that it may also be possible to fortify brain regions with non-invasive stimulation and thus “condition” the brain to better respond to therapy. This could be done by using a noninvasive stimulation technique called transcranial magnetic stimulation, or TMS, to temporarily boost the activity of brain areas that are needed for a successful therapy outcome.

The team of researchers also included Barbara Olasov Rothbaum, Ph.D. of Emory University, a 2012 Distinguished Investigator, Desmond Jay Oathes, Ph.D. of the University of Pennsylvania, a 2016 Young Investigator, and Steven E. Lindley, M.D., Ph.D. of Stanford, a 1995 Young Investigator.