New research using high-resolution positron emission tomography (PET) brain imaging has linked specific symptoms of post-traumatic stress disorder (PTSD), including listlessness and emotional detachment, to specific abnormalities in brain function. This new work, published online September 17th in JAMA Psychiatry, suggests an exciting possible target for future treatments that would “personalize” medication management for this disabling illness.
PTSD is a disabling disorder that causes symptoms such as flashbacks, hypervigilance and emotional numbing or detachment after exposure to trauma. "Our study points toward a more personalized treatment approach for people with a specific symptom profile that's been linked to a particular neurobiological abnormality," Alexander Neumeister, M.D., 2007 NARSAD Independent Investigator Grantee and Co-Director of NYU Langone Medical Center's Steven and Alexandra Cohen Veterans Center for the Study of Post-Traumatic Stress Disorder and Traumatic Brain Injury, told CBS News. "Understanding more about where and how symptoms of PTSD manifest in the brain is a critical part of research efforts to develop more effective medications and treatment modalities."
The researchers used a new, harmless radioactive tracer with the PET scans to examine different regions of the brain presumed to be associated with symptoms of PTSD. The new tracer binds to a class of opioid receptors, known as kappa (KOR); prior research conducted in animals had established a link between KORs and dynorphin (a naturally occurring opioid released by the body during times of stress) with the PTSD symptoms of depression and emotional numbing. In this study the researchers wanted to determine whether there was a similar link in human subjects. They compared the PET scans of healthy volunteers with those of clinically diagnosed trauma victims with PTSD, major depression and generalized anxiety disorder whose symptoms ranged from emotional detachment to isolation.
Their primary finding is that after exposure to trauma, a low availability of KOR in the region of the brain where the amygdala is found (and where the fear response originates), is associated with heightened symptoms of listlessness and emotional detachment (but not anxious arousal or hypervigilance). The secondary finding is that this reduced KOR availability may be linked to more severe symptoms due to lower cortisol levels, suggesting a new role for cortisol as a biomarker for certain types of PTSD symptoms. Cortisol is a hormone naturally released by the body when the corticotropin-releasing factor (CRF) system signals release in response to stress.
"People with cancer have a variety of different treatment options available based on the type of cancer that they have," Dr. Neumeister explained in the interview with CBS. "We aim to do the same thing in psychiatry. We're deconstructing PTSD symptoms, linking them to different brain dysfunction, and then developing treatments that target those symptoms. It's really a revolutionary step forward that has been supported by the National Institute of Mental Health (NIMH) over the past few years in their Research Domain Criteria Project."
The research was conducted in collaboration with scientists at Yale School of Medicine, the School of Medicine at the University of California - San Diego, and the U.S. Department of Veterans Affairs National Center for Post-Traumatic Stress Disorder.