I Am A Real Werewolf

So is shifting something that results because of the fight/ flight reflex in people? I’ve been trying to understand under what circumstances it occurs. If the fight/ flight reflex is the source of it occurring, does that mean the shift happens because the person chose to “fight” or is the simply rage of epinephrine through the body enough to make it result? It would make sense for this to be present as epinephrine tends to overpower prostaglandins (pain causing sensors) of the body, decreasing the pain sensation. Not to mention that the release of epinephrine also stimulates increased heart rate and therefore a higher blood pressure, and more blood circulation. Some even say that the fight/ flight response can even cause us to experience “heightened senses”, which again would make sense as you would be focusing in on whatever person or thing you were about to fight or run from. I’m trying to understand the concept of this from a biological perspective. Biologically, it isn’t impossible for shifting to happen. However, the immense pain one would experience along with the stress on internal organs would cause me to believe that it would be something better left undone for the sake of one’s health. So, any responses to biological stimulators that would cause such a great transformation in one’s body? Are there other hormones that play a role, and possibly ones that exist only in werewolves and not in normal humans? Is there possibly an extra function in the brain of werewolves that controls this?