One of the most unexpected findings of neuroscience over the last 100 years has been the appreciation that the human brain is very much a work-in-progress at the time of birth. The conventional wisdom has been that the major physiological change accompanying growth and development occurred at puberty. All other major systems were thought to be fully formed. We now understand that the human brain goes through enormous changes over the first two decades of life and, in fact remains capable of change into senescence—you can teach an old dog new tricks!
Nowhere is this clearer than in the area of mental illness. Virtually all medical conditions have a major genetic component. Patterns of disease run in families. This is also true for mental illness. The single dramatic exception to this latter observation is the post-natal acquisition of conditions within the spectrum of anxiety disorders including generalized anxiety disorder, panic disorder with or without agoraphobia, phobias, and obsessive-compulsive disorder. It is widely accepted within the psychiatric field that children exposed to emotional, physical, or sexual trauma develop a lifelong condition of post traumatic stress disorder which can manifest itself as any or all of the conditions within the anxiety spectrum or even include disturbances of thought or mood. This pattern of illness is indistinguishable from the genetically transmitted forms of anxiety disorders.
The mechanism involved in the permanent over activation of the Reticular Activating System is not precisely understood but is thought to involve the neurotransmitter epinephrine or adrenaline. Adrenaline is not only a neurotransmitter; it also acts as a hormone mediating the “fight or flight” mechanism in a chordate which produces redistribution of blood flow from the gut and other core areas to the peripheral muscles necessary for flight or fight, increased heart rate to facilitate blood flow, rapid breathing to improve oxygenation of the blood, piloerection to make the animal appear larger, etc. Many of these physical phenomena are associated with anxiety and panic.
We believe that when an immature brain is traumatized, emotionally, sexually, physically (including sensory bombardment), developing neural circuits involving the cellular architecture that mediates the above-described physiological and emotional responses are altered leading to up-regulation or super-sensitization so that they are constantly “On Alert.” This leads to perturbation in glucocorticoids with the possibility of further damage to the victim. It is not reversible.
Currently, oceanographers and marine biologists studying marine mammals are protesting against the US Navy’s plans to study seismic shocks for military purposes. Experts predict these tests will kill hundreds of thousands of dolphins, whales, seals and other marine mammals by creating unimaginable stress levels mediated by epinephrine. The seismic effects are identical to sensory shocks such as sound blasts experienced by mammals on land. The young marine mammals that are not immediately killed will also experience a form of PTSD as their developing brain architecture is permanently altered.