Evidence shows media violence is the leading cause of aggression in people. (Tim Evanson, Wikimedia Commons)

With the nation still recovering from the Sandy Hook shooting last December, tragedy struck again at Washington DC's Navy Yard killing 12. Instantly, politicians directed attention to gun control issues in America and Second Amendment rights. 

From Columbine to Aurora, from Fort Hood to Newtown, these killers have taken several innocent lives. While lawmakers jump to politicize the tragedies that keep occurring, they instantly blame the firearms and Americans' easy access to weapons.

However, are guns really the ones to blame?

Access to firearms may not be the major problem in these mass shootings that are consuming America's attention. There have been at least 50 mass shootings since the beginning of Obama's presidency, according to MSNBC. Because the number of mass shootings is exponentially increasing, there must be a recent factor contributing to these massacres. 

Mental illness and overexposure to media violence are the two leading causes of the increase in violence. According to the Las Vegas Guardian Express, studies show a direct causal link between violent video games and aggression, especially among mentally ill people. Notably, Washington Naval Yard shooter Aaron Alexis was not only mentally ill, but also addicted to violent video games.

People have had access to guns since the 13th century, but mass killings outside of war have been more common in the last 20 to 30 years. Media violence is the only causal factor that has exponentially increased along with the mass shootings in the last few decades. 

According to the American Psychology Association, researchers have discovered that "early childhood exposure to TV violence predicted aggressive behavior for both males and females in adulthood." 

Further research indicates that much of the media that is geared toward children today includes violent content. Whether violent video games or a violent action movie, there is a clear casuation between media violence and adult aggression. As we dig deeper into cases like James Holmes, Adam Lanza and now Aaron Alexis, we find a recurring theme of overexposure to violent media and mental illness. According to Fox News, Alexis had a history of paranoia and sleep disorders along with a host of mental issues. 

Not only do video games and TV cause this violent aggression, but also exposure to violence on the news leads to a vicious cycle of the Mean World Syndrome, a "phenomenon where the violence-related content of mass media convinces viewers that the world is more dangerous than it actually is—and prompts a desire for more protection" than is necessary, according to meanworldsyndrome.com. 

Because of this phenomenon, viewing news violence could cause higher fear, higher aggression towards others and, by default, more violence. This causes a cycle of violent news reporting and thus more acts of violence. 

There is sufficient evidence that proves that media violence is the leading cause of aggression in people. So put down the guns, but consider the other factors that put the guns in the hands of the wrong people before jumping to ban guns and take away our right to bear arms.

Reach Contributor Lisa Battaglia here or follow her on Twitter.