This year, 2018, will be the 100-year anniversary of the end of World War I (WWI), which occurred at 11 AM on November 11, 1918. Wars or any other form of violence never stem from a single cause; there are many contributing factors. Unfortunately, deaths from violence do not necessarily end when wars end; in fact, "more Americans have died from guns in the United States since 1968 than on battlefields of all the wars in American history."1
The scientific capability to understand and prevent violence lags behind the technical capability of weapon development. If this trend continues, how many violent individuals, groups, or countries will have access to highly sophisticated weapons of mass destruction? By looking at past events throughout history, individuals can better understand the factors that contributed to violent actions and events, and then they can use that knowledge to reduce those factors, and thus, prevent future catastrophes.
There are many motivators that can lead to wars; common motivators include economic or territorial gain, religious conflicts, nationalism, racism, revenge, civil or revolutionary reasons, or for defensive purposes.2
Certain brain impairments increase the risk of violence; for example, injury to the right ventromedial prefrontal cortex impairs empathy, and injury to the orbital frontal cortex and other areas reduces impulse control.3
If either or both sides of a conflict are excessively influenced by individuals with brain impairments associated with violence, this may increase the risk of violence and war. However, when both sides of a conflict are influenced by individuals who are high-functioning with intact mental capabilities, the futility of war can more easily be seen, and thus, more readily avoided; a good example of this was the peaceful resolution of the Cuban missile crisis.
Warfare environments encourage the proliferation of infectious diseases. The movement of soldiers into regions where they lack immunity to local pathogens, crowding, malnutrition, stress, and deprivation during a war are all conducive to serious infectious and emerging diseases in soldiers, prisoners, refugees, as well as the general population. In fact, often, epidemics persist and expand even after a war ends. Examples of this include: the plague of Athens that occurred during the Peloponnesian War in 429 BC, bubonic plague that spread from the Venetians escaping Kaffa in 1347, the first appearance of syphilis in 1494/1495 that sprung up either from French troops returning from Naples or Columbus returning from the New World, typhus which followed Napoleon's retreat from Moscow in 1812, typhus and malaria which spread during the Korean War, cerebral malaria among Vietnam veterans, and Mycoplasma
infections which sprung up in Gulf War veterans and their family members.4