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David Baxter PhD

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Brain Chemistry Plays Important Role in PTSD
US Medicine
Jaunary 30, 2009

While post-traumatic stress disorder (PTSD) is generally considered psychological illness, scientists are coming to understand that the illness has severe physical ramifications. Those suffering from PTSD can come to suffer physical damage from the stress caused by the disease.

?Sometimes the stress response, if extended, can be more damaging than the stressor itself,? explained Dr. Steven Southwick, deputy director of the clinical neurosciences division of the National Center for PTSD, at the Department of Defense?s (DoD?s) Warrior Resilience Conference held here in November.

Damaging Delicate Brain Functions
The complex emotional and mental systems that have put humans at the top of the food chain can be a detriment when dealing with extreme stress, Dr. Southwick noted. ?Animals rarely experience damage from their own stress response, because animals can turn off their stress response,? he explained. ?Humans can become stressed from ideas, from perceptions, thoughts and emotions. This rumination can activate the stress response. And when can this stress response cause the most damage? When the stress is unremitting.?

Unremitting stress is exactly what occurs when a patient suffers from PTSD. And, as scientists and physicians are starting to discover, chronic, unremitting stress can actually damage parts of the brain.

?In tree shrews, for example, chronic stress causes shortening and decreased branching of hippcampal neurons, reduced synaptic connections, a reduced flow of information and increased levels of cortisol and noreprinephrine,? Dr. Southwick explained. Excess cortisol damages the hippocampus, impairs the ability to turn off the stress response and causes more excess cortisol, creating a vicious cycle. MRIs have shown that the hippocampus is smaller in people with PTSD, possibly due to damage caused by excess cortisol.

?The other system that can become compromised due to PTSD is the neuroadrenaline system, which is critically important for staying alive,? he said. ?Acute stress, fear and novelty increase central and peripheral noreprinephrine (NE). NE helps humans selectively attend to those stimuli in their environment that are critical for survival. It?s also important for vigilance and cardiovascular response. It?s a critical part of the alarm system in my brain.?

Controllable stress ? stress caused by a singular event with a defined end ? can be good for the human body, inoculating it against future stressful events. But stress that cannot be controlled?stress caused by the unremitting recollection of a previous stressor?can be harmful to the nervous system over time. ?NE can become sensitized, so that the next time a stressor comes along, an individual releases more stress hormone [than is really needed],? Dr. Southwick explained.

Family members frequently complain of a PTSD sufferer overreacting to everything. One explanation for this may be that they are releasing more NE and more cortisol than is necessary.

Stress as Inoculation
?The [American Psychological Association] defines resilience as the process of adapting well in the face of adversity, trauma, tragedy, threats or even significant sources of stress,? he explained. ?Most people understand resilience to be multidimensional. The National Center for PTSD (NCPTSD) is in the process of developing a scale to measure resilience, [looking at] individuals who have the right stuff to make it through highly stressful situations. How do they think? How do they regulate their emotions? How do they behave??

Scientists at the NCPTSD have discovered that resilience is incredibly complex, with numerous mediating factors. ?There are developmental factors. If you expose infants to uncontrollable stress, as adults they?re more likely to develop PTSD,? Dr. Southwick said. ?They will be hyperreactive and they don?t handle stress at all. [However] exposing monkeys to moderate amounts of stress [shows they] handle stress better in the future.?

?It?s called stress inoculation,? he said. ?Induced stress increases an organism?s capacity to effectively manage future stress. Too little, and there?s no growth. Too much, and it becomes destructive.?

There are also neurobiological factors, specifically concerning an amino acid called NPY, which is released with NE when the sympathetic nervous system (SNS) response is strongly activated. NPY inhibits the continued release of NE, so that the SNS does not ?overshoot,? a person does not stay hyperreactive and aroused for long periods of time, and it helps bring NE back to baseline.

?The soldiers who performed the best had the highest levels of NPY under high stress,? Dr. Southwick revealed. ?Yes, they had high levels of NE, but they had high levels of this amino acid that brought them back to baseline very quickly.? Those soldiers with reduced levels of NPY had a much harder time distressing, and bringing NE back to baseline.

Psychosocial factors are also important. Positive emotions, the ability to regulate emotions, cognitive flexibility, possession of a moral compass, social support, training, rapid recovery and understanding the purpose and meaning of the mission are all factors that lessen the chances of a soldier developing PTSD, Dr. Southwick explained. And having a mentor with these attributes can also be important. ?Resilient role models can transmit attitudes, values, and patterns of thought and behavior,? he noted. ?Imitation is a very powerful way of learning.?

Also, a soldier?s method of coping with stress will help determine their chances for developing PTSD. ?Nearly all of the resilient soldiers that we interviewed used active coping,? Dr. Southwick explained. ?It?s gathering information, acquiring skills, confrontation when needed, problem solving, seeking social support. It is not denying the problem, waiting for the dust to settle, avoiding or withdrawing.?

Asked what DoD should focus on in training soldiers to handle stress, Dr. Southwick said that stress inoculation, unit support, realistic training exercises and, most importantly, forewarning them about the mental stresses that they will naturally experience, are all critical to making sure servicemembers have the best chance of leaving a war zone free of combat-related stress disorders.


Account Closed
Great article!

I was told by my trauma therapist that it is equally important to get rid of the adrenalin build-up after an amygdala hijack. Exercising until you sweat is the best way. Too much adrenalin can be just as damaging as all the other chemicals the article talks about.
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