Researchers have linked a certain opioid receptor (associated with emotions) to specific trauma symptoms, including sadness, emotional detachment and listlessness.
The brain imaging study, conducted by researchers at New York University Langone Medical Center, could one day aid in the development of targeted, personalized treatment for post-traumatic stress disorder (PTSD).
“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,” said lead author Alexander Neumeister, M.D., director of the molecular imaging program in the departments of Psychiatry and Radiology at New York University School of Medicine.
“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 study confirms a growing body of evidence linking a particular set of symptoms to specific brain circuits and chemicals, and moves away from “one-size-fits-all treatments” and toward more individualized medication regimens.
“We know from previous clinical trials that antidepressants, for example, do not work well for dysphoria and the numbing symptoms often found in PTSD,” said Neumeister.
“Currently available antidepressants are just not linked specifically enough to the neurobiological basis of these symptoms in PTSD. Going forward, our study will help pave the way toward development of better options.”
“People with cancer have a variety of different treatment options available based on the type of cancer that they have,” he said. “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 study compared the brain 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.
Participants were given a harmless radioactive tracer that binds to and illuminates a class of opioid receptors, known as kappa, when exposed to high-resolution positron emission tomography (PET).
Chronic exposure to stress, such as the case with PTSD, wears down on kappa opioid receptors, causing the receptors to retract inside cells. As a result, patients can experience dysphoria, characterized by feelings of hopelessness, detachment and emotional unease.
Results showed that fewer available kappa opioid receptors in the brain regions believed to govern emotions were associated with more intense feelings of dysphoria, but not feelings of anxious arousal.
“This is the first brain-imaging study to explore any psychiatric condition using a protein that binds to the kappa opioid receptor system,” said Neumeister.