Traumatic Brain Injury and PTSD may Not be Separable; Evidence Demonstrates Shared Symptoms and Pathophysiology
Post Traumatic Stress Disorder (PTSD) and Traumatic Brain Injury (TBI) have been often been viewed as two distinct conditions, one with an “emotional” cause and the other with a “physical” cause. It has been recognized for some time that these conditions can produce similar symptoms, such as problems with sleep, concentration, memory and mood. As noted by the authors of a literature review published in Current Neurology and Neuroscience Reports, “increasingly symptoms previously presumed to be specific to PTSD or TBI are being identified in both disorders.” These include symptoms more commonly associated with TBI such as headache, dizziness, balance and vision problems. Evidence has also demonstrated that patients with a history of TBI are more likely to meet criteria for PTSD than others with similar intensity injuries and that patients who are also diagnosed with PTSD are significantly more likely to report persistent cognitive or sensory problems after a TBI.
The authors conclude based on their literature review that TBI and PTSD may not, in fact, be separable, that “PTSD and TBI may be intimately related not just at the level of symptoms and etiology, but also at the level of pathophysiology.” New evidence, the reviewers note, shows that after both physical brain injury and traumatic stress changes can occur in each of the three interacting systems that coordinate the body’s response to the experience or expectation of major injury, the immune, endocrine and neuromodulatory neurotransmitter systems. For examples,
- the immune system is activated when there is acute tissue damage and when a serious threat is perceived. A complex neuroinflammatory response has been found in both conditions.
- The neuroendocrine system also plays a role in regulating the body’s response to stress and can be physically damaged in a TBI (prior posts have discussed the vulnerability of the pituitary gland and symptoms of dysfunction following this damage.) Acute and persistent changes in neuroendocrine function have been noted in individuals with a history of TBI and in individuals with psychiatric diagnoses, including PTSD.
- Changes in a range of neuromodulatory neurotransmitter systems have also been observed following both TBI and PTSD. One of key neurotransmitter systems is called the “Catecholamine” system. Catecholamines are hormones made by your adrenal glands; the three most commonly known ones are epinephrine (adrenaline), norepinephrine and dopamine. They regulate physiological functions such as your heartbeat and breathing rate.
The recognition that TBI and PTSD may not be separable has important implications for clinical care.
Consideration should be given to using treatment tools from both the TBI and PTSD realms. The reviewers also note that the complex interaction of these three bodily system for responding to stress and injury can impact different patients in different ways and at different times, indicating a need for careful monitoring of individual responses, particularly in the use of pharmacotherapy: “[T]he complexity of the primary and then compensatory changes in the systems involved, along with evidence that these changes may evolve over time and exhibit different relative strengths in different patients at different times, highlights the necessity of being open to the same intervention – particularly a pharmacotherapy – having differing effects, in different patients, at different times, or even on different symptoms.“
The challenge of this information is that it highlights the incredible complexity of the brain and its interaction with bodily systems. The opportunity is that it opens doors to explore a wider range of treatment options.