How PTSD Affects The Brain, According To Researchers

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Post-traumatic stress disorder, or PTSD, is an anxiety disorder in which the experience of a traumatic event has long-term, serious consequences. People with PTSD, who number 3.6% of all American adults, according to the National Institute of Mental Health, experience symptoms including flashbacks, nightmares and hyper-vigilance as a result of their traumatic experiences, sometimes many decades after the trauma itself happened. Neurologists explain to Bustle that PTSD actually has a complicated relationship with the brain — and that while there are clearly many ways in which PTSD changes neurobiology, there are a huge amount of unanswered questions about what PTSD looks like in the brain and why.

"Severe and chronic post traumatic stress disorder has been found to change not only the function but the structure of the brain over time," Dr. Sean Clouston, Associate Professor of Public Health at the Department of Family, Population and Preventative Medicine at Stony Brook Medicine and a PTSD researcher, tells Bustle. Understanding these physical changes, however, can be complicated.

It's sometimes difficult for researchers to know whether PTSD has caused physical changes in the brain, or whether those physical characteristics were already there. Dr. Shaili Jain, a PTSD expert and author of The Unspeakable Mind, explains that there are three main areas of the brain implicated in PTSD: the hippocampus, the frontal lobe, and the amygdala. The hippocampus, she explains, "is a part of the brain that's located in the temporal lobe where we process memories. It's smaller in people who have PTSD, but we don't know why." It's a case of chicken and egg, she notes: "We don't know if they were born with a smaller hippocampus and that somehow made them more vulnerable to PTSD, or if it shrunk after they were exposed to trauma."

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The frontal lobe and the amygdala can also bear the physical marks of PTSD. The amygdala is the part of the brain where we process emotions like fear and anger, while the frontal lobe is where we execute judgement and plan our actions, Dr. Jain tells Bustle. "The amygdala is over-active in people who have PTSD, and the frontal lobe is under-active," she says. The amygdala's over-sensitivity is why "people with PTSD see danger when danger isn't there," she explains, while the damage to the frontal lobe explains symptoms like recklessness, impulsivity and anger. "In PTSD," she says, "the frontal lobe isn't thinking things through. It's not processing information correctly."

PTSD isn't just a case of three independent brain areas operating poorly, though. The pre-frontal cortex, a part of the frontal lobe, and the hippocampus are part of a system that helps us solidify our memories. "It's the system that binds together multiple components of the memory," Professor Israel Liberzon, head of Texas A&M's department of psychiatry and a psychiatrist who's done extensive research on PTSD, tells Bustle. "These mechanisms are dependent on the integrity and appropriate function of hippocampus and prefrontal cortex and appropriate communications between the two." In people with PTSD, he says, researchers can track changes all through the prefrontal cortex and hippocampus, all the way down to their molecules.

Their brain turns on both brain and body pathways and activates stress response systems.

Beyond those three areas, PTSD has broader effects on the brain's overall functioning. "In some studies, individuals with PTSD have been found to have depletions in the brain's gray matter, along with changes to connections between sections of the brain," says Dr. Clouston. "These things are critical to the brain's ability to learn, remember, and make new connections between ideas." You need gray matter (as distinct from white matter, the actual cells of the brain) as an essential part of brain health.

The other area that shows physical signs of PTSD is our neurochemistry, or the balance of chemicals, including hormones, that interact with our brains at all times. "There's something going on with cortisol, which is the human stress hormone," Dr. Jain tells Bustle, "but contrary to what people might tell you, it's a very complicated picture." Cortisol levels in people with PTSD are often lower than in others, she explains, while other chemicals, such as noradrenaline and adrenaline, are spiking. "These are released by the body when goes into fight or flight mode. We know that in people with PTSD, those chemicals are just floating around in their bodies, at much higher rates than they should be and for a lot longer," says Dr. Jain.

The neurotransmitter serotonin, which is so often the focus of mood disorder treatment, is also impacted by PTSD. Research shows that people with PTSD often appear to have serotonin imbalances. This, says Dr. Jain, probably accounts for some of the mood symptoms that accompany PTSD, like depression, irritability and anger.

The long-term effects of PTSD are one thing, but what happens in the brain of somebody with PTSD when they're experiencing a traumatic flashback — an episode where they seem to relive the traumatic event, with all of the accompanying sensations and emotions? Flashbacks are still mysterious for neurologists, because they aren't like a regular memory; the brain acts as if the trauma is happening all over again. "During a flashback," says Dr. Clouston, "the brain acts much like it would when individuals are actually experiencing a severely traumatic event, often the most stressful and frightening event of a person's life. Their brain turns on both brain and body pathways and activates stress response systems." The body takes cues from the brain and enters high alert, even if there's no threat whatsoever.

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Studies have revealed that when it's experiencing flashbacks, a brain with PTSD doesn't just seem to relive what's happened; it actively goes through all its reactions to the event again. A study in 2016, says Dr. Jain, looked at images of the brain while patients were having flashbacks, and found that the visual cortex and the brain areas that control spatial and temporal awareness both showed a lot of activity.

The visual cortex, she tells Bustle, "would explain the vivid nature of the flashbacks, which is why people who have flashbacks feel they're reliving the trauma and it feels so real to them." The spatial and temporal areas, meanwhile, mean that the person undergoing a flashback loses their orientation in time and space; they're transported back to the point of their trauma, even if it's thousands of miles and many years away.

The brain also feeds the body information about how to act against the perceived repeated threat. When a flashback happens, says Dr. Clouston, the brain "starts the body's systems to facilitate the body's readiness to respond how it needs to: the heart rate increases and the body makes signals and changes needed to facilitate movement and action." This is why people undergoing flashbacks often move or act as they did when they were traumatized the first time; their neurobiology is directing their physical actions, whether it's hiding, fighting or running away.

There are still a lot of unanswered questions about the neurological effects of PTSD and how it changes the brain. Dr. Clouston points to one recent study showing that PTSD might cause the brain to degenerate over time, causing heightened risk of disorders like dementia. However, our understanding of PTSD will grow as we get better technologies to examine the brain's neurochemistry and structure. Dr. Jain explains, "The picture we have is only as good as the tools that we have."

If you or someone you know is seeking help for mental health concerns, visit the National Alliance on Mental Health (NAMI) website, or call 1-800-950-NAMI(6264). For confidential treatment referrals, visit the Substance Abuse and Mental Health Services Administration (SAMHSA) website, or call the National Helpline at 1-800-662-HELP(4357). In an emergency, contact the National Suicide Prevention Lifeline at 1-800-273-TALK(8255) or call 911.