PTSD is generally, in spite of changes to the brain which show on MRI and fMRI, considered to be a psychiatric or psychological illness which can be treated with cognitive behavioural therapy or psychological therapy and psychiatric medications.
I would like to put forward the hypothesis that PTSD is actually a physiological issue, specifically one having to do with the mitochondria and electron chain transport (a facet of cellular respiration, how the body manufactures energy), one which manifests as a psychological disorder, in response to immune changes caused by epigenetics – changes to the DNA through stress — leading to white matter and neurological degeneration. This hypothesis is supported by the fact that regulatory T cells, part of of the immune response, are altered in people with PTSD by changes in the thalamus and pituitary gland, by evidence of mitochondrial oxidation, and by changes to the brain in the form of tau protein and amyloid beta plaques in the brains of deceased veterans. Mitochondrial dysfunction has been proven to be a common upstream driver in the development of such plaques.
PTSD is not, regrettably, a diagnosis of exclusion, which allows for the misdiagnosis of traumatic brain injury or mefloquine toxicity syndrome as PTSD. Nor is it something commonly tested for with brain scans. The diagnosis itself, though in the past called shell shock or combat fatigue, is only about 20 years old, and treatment has primarily focuses on overcoming functional or relationship difficulties than an underlying physiological issue. One of the more interesting aspects of PTSD is that it only effects approximately 10% of the population. This is interesting in light of the fact that inborn errors of metabolism occur in about 1:1,500 people and are largely undiscovered until adulthood.
If this theory is correct, it certainly changes not just how the disorder is viewed, but also how it is treated. To use a metaphor, the human body and functioning is a car, and the mitochondria are the spark plugs and fuel line. By addressing functioning and symptoms alone, you are going to the destroy the car, because you are essentially expecting high performance from a car that is running on gas fumes or has sugar in the tank.