The fight-or-flight response (also called hyperarousal, or the acute stress response) is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival. It was first described by Walter Bradford Cannon. His theory states that animals react to threats with a general discharge of the sympathetic nervous system, preparing the animal for fighting or fleeing. More specifically, the adrenal medulla produces a hormonal cascade that results in the secretion of catecholamines, especially norepinephrine and epinephrine.The hormones estrogen, testosterone, and cortisol, as well as the neurotransmitters dopamine and serotonin, also affect how organisms react to stress.
Medications that help PTSD sufferers include serotonergic antidepressants (SSRIs), like fluoxetine (Prozac), sertraline (Zoloft), and paroxetine (Paxil), and medicines that help decrease the physical symptoms associated with illness, like prazosin (Minipress), clonidine (Catapres), guanfacine (Tenex), and propranolol.