The root of post-traumatic stress disorder, or PTSD, is a memory that cannot be controlled. It could interfere with daily activities or appear as night terrors or flashbacks.
Decades of treating military veterans and survivors of sexual assault have left little doubt that traumatic memories function differently than other memories. Researchers at Yale University in Connecticut and the Icahn School of Medicine at Mount Sinai in New York set out to find empirical evidence of those differences.
The team performed brain scans on 28 people with PTSD while they listened to recorded accounts of their own memories. Some of the memories were neutral, some were “sad,” and some were traumatic.
The scans showed obvious differences, the researchers reported in an article published in the journal Nature Neuroscience. Those who heard the sad memories, which often involved the death of a family member, consistently showed greater activity in the hippocampus, the part of the brain that organizes and contextualizes memories.
When the same people heard traumatic memories—of sexual assaults, fires, school shootings, and terrorist attacks—the hippocampus was not involved.
“The brain is in a different state in the two memories,” explained Daniela Schiller, co-author of the study. She said therapies for PTSD often sought to help people organize their memory so they could see it as distant from the present.
“Now we found something that can potentially explain it in the brain,” he noted. “The brain does not seem to be in a state of remembering: it seems to be in a state of present experience.”
Traumatic memories appeared to involve a different area of the brain—the posterior cingulate cortex, or PCC, which is usually involved in internally directed thinking, such as introspection or daydreaming. It is not known as a memory region. The more severe the person's PTSD symptoms were, the more activity appeared in the PCC.
The findings raise a hotly debated question: Should clinicians encourage people with PTSD to expose themselves to their most traumatic memories? Ilan Harpaz-Rotem, co-author of the study, said revisiting the memory was a crucial element of the treatment.
“You help the patient build a memory that can be organized and consolidated in the hippocampus,” he said.
Ideally, such treatments can help transform the traumatic memory into one that is much more like ordinary sad memories. “It's like putting a blockade in the right place,” said Harpaz-Rotem. “If I can access a memory, I know it is a memory. “I know it’s not happening to me right now.”
If biological markers of PTSD can be identified, it would reconcile differences in what experiences constitute trauma, said Brian Marx, deputy director of the Division of Behavioral Science at the National Center for PTSD, who was not involved in the study. While most experts agree that car accidents, sexual assault, or military combat are traumatic events, they disagree over whether experiences like racism or pandemic stress should be seen as grounds for a PTSD diagnosis.
Marx called the research “fascinating,” but inconclusive, noting that it did not include a comparison group of study subjects without a PTSD diagnosis, did not specify how long ago the traumatic events occurred, and did not specify whether the study subjects had received psychotherapy. .
Additionally, he said it was unlikely to resolve debates about whether treatments for PTSD should include exposure to traumatic memories, because the literature shows that outcomes are highly individualized.
“Our treatments are imperfect,” he admitted. “They don't work for everyone the same way.”
By: ELLEN BARRY
BBC-NEWS-SRC: http://www.nytsyn.com/subscribed/stories/7026162, IMPORTING DATE: 2023-12-12 18:50:06
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