I continue to think a lot about the connections between mild TBI and PTSD. After going off the rails last month over some stressful stuff at work… and continuing to struggle with stress and how it affects me, I cannot help but see a lot of connections between the stress I’m under, the way I respond to it, and the way my brain has been working lately.
This article came out back in February, 2012, and I may have blogged about it before — it’s worth mentioning again:
ScienceDaily (Feb. 15, 2012) — UCLA life scientists and their colleagues have provided the first evidence of a causal link between traumatic brain injury and an increased susceptibility to post-traumatic stress disorder.
The motivation behind the study, which was conducted in rats, was the observed correlation of traumatic brain injury, or TBI, and PTSD, particularly in military veterans returning from service overseas, said Michael Fanselow, a UCLA professor of psychology and the senior author of the study.
The reasons for this correlation are unknown. It could be simply that the events that cause brain injury are also very frightening and that the link between TBI and PTSD could be merely incidental. Fanselow and his colleagues, however, hypothesized that the two “could be linked in a more mechanistic way.”
Using procedures to separate the physical and emotional traumas, the scientists trained the rats using “fear conditioning” techniques two days after they experienced a concussive brain trauma — ensuring the brain injury and the experience of fear occurred on different days.
“We found that the rats with the earlier TBI acquired more fear than control rats (without TBI),” said Fanselow, a member of UCLA’s Brain Research Institute. “Something about the brain injury rendered them more susceptible to acquiring an inappropriately strong fear. It was as if the injury primed the brain for learning to be afraid.”
To learn why this occurred, the researchers analyzed a small piece of brain tissue, the amygdala, which is the brain’s critical hub for fear learning.
“We found that there are significantly more receptors for excitatory neurotransmitters that promote learning,” said Maxine Reger, a UCLA graduate student of psychology in Fanselow’s laboratory and the lead author of the study.
“This finding suggests that brain injury leaves the amygdala in a more excitable state that readies it for acquiring potent fear,” Fanselow said.
The research was funded by the National Institutes of Health, the U.S. Department of Defense and the UCLA Brain Injury Research Center.
Co-authors of the study were David Hovda, a professor of neurosurgery and of molecular and medical pharmacology at the David Geffen School of Medicine at UCLA and director of the UCLA Brain Injury Research Center; Andrew Poulos, a postdoctoral fellow in Fanselow’s laboratory; Floyd Buen, a former graduate student in Hovda’s laboratory; and Christopher Giza, an associate professor of neurosurgery at the Geffen School of Medicine.
The research was a collaboration between Fanselow’s laboratory, which studies neural mechanisms of anxiety disorders, and Hovda’s laboratory, which investigates brain injury.
“One of UCLA’s great strengths is the spirit of collaboration that allows scientists from very different departments to combine their very different expertises to answer important but difficult questions,” Fanselow said.
This is very encouraging (if I haven’t said it before). The fact that clinical researchers are looking at the biomechanical actions of mild TBI and PTSD opens up new routes for better understanding more pieces of this puzzle. I’ve said a number of times that TBI and PTSD are intricately intertwined in some really fundamental ways, many/most of which are experientially biochemical in nature. And the fact that researchers are now paying attention to this and publishing papers about this, really gives me hope for the future of handling this “co-morbid” condition.
I have also long believed (and I think also said) that mild TBI is especially vulnerable to PTSD development, because by its very nature it is confusing at the most fundamental level — which leads to continual activation of the fight-flight reflex, which ultimately builds up a biochemical load that’s heavy on the stress hormone side — and light on the rest-digest impulse. Mild TBI and its successive “micro-traumas” of continuously baffling and inexplicable experiences, many of which are either negative/threatening or perceived to be negative/threatening, is the experiential equivalent of all those subconcussive hits sustained in football, and the biochemical overload of stress hormones that builds up, day after interminable day, serves to further fry the system and the brain and the circuits which would normally serve to chill us out and manage to find a way around (or through) the troubles in one piece.
Unfortunately, I’m not a clinical researcher with an internationally recognized facility, so there’s only so much that I can do to advance this understanding in the circles where people make the diagnoses and treatment decisions. But I can at least do my part here, in hopes that the people who are actually affected by mTBI and PTSD will find some answers — and relief. And those who treat people with PTSD and/or TBI would be well-served to explore the connections between the two. It is such an obvious connection, when you stop dismissing life experience as “anecdotal” that it surprises me that no one is confronting it head-on. Or that anyone is still being territorial about their explanations for why some of us do and experience the things we do. If the professions would cross-pollinate and cross-promote, they would uncover a vast opportunity to not only expand their service, but come up with a whole new slew of approaches that actually work with those suffering from stress-hormone-overload-induced dysfunction/disorders in the aftermath of TBI.
I can’t control the fields/industries, but I can always hope. And keep working…