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Specific Brain Activity May Identify Patient Responsiveness to PTSD Treatment

August 3, 2017
Patients with post-traumatic stress disorder who improved following prolonged exposure therapy showed similar brain activity patterns after completing emotional tasks, which was predictive of individual responsiveness to psychotherapy.

With Gregory A. Fonzo, PhD

Exposure therapy is a common treatment for people who have post-traumatic stress disorder (PTSD), but not all patients respond equally and some do not respond favorably.

Teasing out treatment responders from those who don't respond to prolonged exposure therapy for PTSD was the focus of 2 studies published in the American Journal of Psychiatry.1,2

Imaging Patterns Predictive of Therapeutic Response

By studying the brain patterns following reactions to emotionally focused tasks, a team of researchers lead by Amit Etkin, MD, PhD, associate professor of psychiatry and behavioral sciences at Stanford University School of Medicine in California, sought to identify functional characteristics that might distinguish patients with PTSD who presented as more responsive to treatment.1,2

"These randomized clinical trials aimed to fill in a gap in our knowledge about responsiveness to exposure therapy for people looking to better manage their PTSD," said lead author Gregory A. Fonzo, PhD, a postdoctoral psychology fellow at Stanford. Having biomarkers or clinical measures will lead to more effective therapy for every one of these patients.

Responsiveness to treatment for PTSD can be predetermined.

Testing Responsiveness to Exposure Therapy

In the 1st study, patients with PTSD were randomized to receive immediate prolonged exposure therapy (N = 36) or were waitlisted for therapy (N = 30).1  They were asked to complete 3 emotionally focused tasks while undergoing functional magnetic resonance imaging (fMRI).

According to the authors, the likelihood of gaining improvement from prolonged exposure was gated by the level to which prefrontal engagement occurred during the processing of emotional stimuli. Individuals with mental disorders exhibited a common pattern of disruption similar to the multiple demand network, an integrated frontoparietal system, assessed using fMRI.1,3

“These findings demonstrated a common pattern of disruption that parallels the multiple demand network seen in intact cognition,” said Dr. Fonzo, "so we were able to show that exposure therapy was working."

The 2nd study followed a similar protocol as the first study but added a subgroup receiving immediate exposure treatment who underwent single-pulse transcranial magnetic stimulation during fMRI to access for predictive activation patterns.2  Exposure therapy produces a significant improvement in PTSD symptoms and lessens depression alongside a change in brain activation by producing a deliberate reduction of negative emotion when completing an emotion-base task, according to the authors.

In those undergoing prolonged exposure therapy, 2/3 of patients showed a 50% reduction in symptoms, and overall there was an 80% remission rate.2 The remainder of patients (33%) did not complete the therapy.

Need for Clinically Applicable Tools

"Individuals who had the greatest response to prolonged exposure therapy demonstrated a specific brain activity pattern when completing emotional reactivity and regulation tasks," Dr. Fonzo told Practical Pain Management, "Observed patterns in the prefrontal cortex on functional magnetic resonance imaging (fMRI) that paralleled individual responses to tasks could be used to develop clinically useful tools in the future.

"In patients with PTSD, those who demonstrated greater activation of prefrontal regions in response to emotional cues before undergoing treatment benefited the most from exposure.1,2

"While fMRI is not a practical assessment tool in the clinical setting, now that we have the ability to recognize responses to attention getting reactions, we know that patients who demonstrate an ability to override superficial cues and distinguish emotional responses to threats will respond favorably to prolonged exposure therapy," said Dr. Fonzo.

While we don't know why some people who develop PTSD respond better than others to exposure therapy, genetics, and early life experiences likely play a role, particularly in patients who do not respond favorably, he said.

These findings bring us closer "to offering individuals the right treatment, but for those not likely to respond, the next step will be to tailor a different therapeutic approach for them. In addition, we will be looking to test more accessible tools such as the electroencephalogram (EEG) to distinguish favorable responders in the clinical setting," Dr. Fonzo told Practical Pain Management.

"Since we know that people who have PTSD often have chronic pain conditions too, being able to identify the right treatment approach to manage their PTSD will create a better circumstance for addressing the patient's pain, overall," Dr. Fonzo concluded. 
Last updated on: August 3, 2017
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