“Fight or flight” is likely a term you've heard before, however, the term falls short of capturing the entire survival response system. This is why professionals now refer to the process as “fight, flight or freeze.” It is a term referring to the autonomic nervous systems response to perceived danger. As a whole, this is a brilliant survival mechanism for humans! A classic example would be if you’re crossing the street and a bus comes barreling your way, you realistically don’t have time to calculate the speed of the bus, as well as your own speed, to determine a safe course of action, in order to escape the perceived threat to your life. By the time you do the math and then make a sound decision, you’d be struck. This is where we want the survival mechanism of fight or flight to kick in, milliseconds prior to our reasoning or logic, and promptly signal to our legs to run. No thinking, no processing or rationale- just run.
There are two main systems, which the brain gives directions to, during the “fight, flight or freeze” response 1) the sympathetic nervous system and 2) the parasympathetic nervous system. These two systems are what make up the autonomic nervous system. The sympathetic nervous system is primarily responsible for anxious responses (aka “Fight or Flight”), whereas the parasympathetic nervous system predominantly inhibits the body from overworking and restores the body to a calm and composed state, which could include swinging to an extreme “Freeze” response. When the Fight, Flight or Freeze response is underway, the more logical thought processes in the prefrontal cortex are practically unavailable. The body simply responds out of primal survival mechanisms to “keep you alive” (as it is wired to do).
The treatment of PTSD varies from individual to individual, based upon the severity of terror responses, somatic responses, comorbid diagnosis, resiliency and more. The physiological hyperarousal and/or hypoarousal responses that individuals experience (fight, flight or freeze) are typically prominent features that need addressed. This can include examples such as chronic emotional numbing, dissociative responses and panic.