The chemical composition of the human brain has always been fragile, being put in a state of battle can produce chemicals that have a massive effect on the body and mental state of being. Further factors include outside aggressors such as foreign chemicals and one’s own self. (PTSD) or Post Traumatic Stress Disorder can only be developed if one has been exposed to a very traumatic event evolving an actual threat or serious injury, or a threat to a physical integrity of oneself or others. Most importantly a clinical experience with PTSD diagnosis has shown that most people who have been exposed to a horrific event do not necessarily acquire PTSD although that is the main cause of it; there was a vast amount of individual differences regarding the capacity or threshold to take a traumatic event. Very many illnesses have an effect on American literature, and this is because of how Agent Orange, Gulf War Syndrome, and PTSD came about. They affect literature by the way the media novels and authors portray them. Different people react to events differently; no one person is the same as one another. Like pain the traumatic experience is filtered through a cognitive and emotional process called appraisal. PTSD can take a very psychological and emotional toll on ones personal life, such as resentment and possibly force one to act out in odd ways. There are three different categories: pre-traumatic, traumatic and post traumatic factors. Pre traumatic could be anything from familiar psychiatric illness, parental poverty, childhood trauma, neuroticism, introversion, divorced parents before age 10, Etc. Post traumatic environment have also been known to relate to later development of PTSD. Because of the post military support and dysfunctional patterns of social interaction, this has been noticed to lead to PTSD, as well as other medical issues and psychiatric disorders.