Mass shootings can be motivated by political ideologies ( i.e. white nationalism , neo-Nazism , black nationalism and left-wing beliefs ) , misanthropy , terrorism , mental illness , extensive bullying , among other reasons . Forensic psychologist Stephen Ross says that extreme anger and the thought shooters are working for a cause , rather than mental illness , is most often the explanation . A study by Vanderbilt University researchers found that " fewer than 5 % of the 120,000 gun-related killings in the United States between 2001 and 2010 were perpetrated by people diagnosed with mental illness " . John Roman of the Urban Institute argues that , while better access to mental health care , restricting high powered weapons , and creating a defensive infrastructure to combat terrorism are constructive , they do n't address the greater issue , which is " we have a lot of really angry young men in our country and in the world . " Author Dave Cullen , who wrote the 2009 book '' Columbine '' , on the infamous 1999 Columbine High School massacre and the perpetrators Eric Harris and Dylan Klebold . Cullen described Harris as an " injustice collector " in his 2009 book '' Columbine '' . He expanded on the concept in a 2015 '' New Republic '' essay on injustice collectors , identifying several notorious killers as fitting the category , including Christopher Dorner , Elliot Rodger , Vester Flanagan , and Andrew Kehoe . Likewise , mass shooting expert and former FBI profiler Mary O'Toole also uses the phrase " injustice collector " in characterizing motives of some mass shooting perpetrators . In relation , criminologist James Alan Fox contends that mass murderers are " enabled by social isolation " and typically experience " years of disappointment and failure that produce a mix of profound hopelessness and deep-seated resentment . " Jillian Peterson , an assistant professor of criminology at Hamline University who is participating in the construction of a database on mass shooters , noted that two phenomena surface repeatedly in the statistics : hopelessness and a need for notoriety in life or in death . Notoriety was first suggested as a possible motive and researched by Justin Nutt . Nutt stated in a 2013 article , " those who feel nameless and as though no one will care or remember them when they are gone may feel doing something such as a school shooting will make sure they are remembered and listed in the history books . " In considering the frequency of mass shootings in the United States , criminologist Peter Squires says that the individualistic culture in the United States puts the country at greater risk for mass shootings than other countries , noting that " many other countries where gun ownership is high , such as Norway , Finland , Switzerland and Israel . . . tend to have more tight-knit societies where a strong social bond supports people through crises , and mass killings are fewer . " He is an advocate of gun control , but contends there is more to mass shootings than the prevalence of guns . The Italian Marxist academic Franco Berardi argues that the hyper-individualism , social alienation and competitiveness fomented by neoliberal ideology and capitalism creates mass shooters by causing people to " malfunction . " Harvard sociologist Robert J. Sampson writes : " Family structure is one of the strongest , if not the strongest , predictor of variations in urban violence across cities in the United States . The close empirical connection between family breakdown and crime suggests that increased spending on crime-fighting , imprisonment , and criminal justice in the United States over the last 40 years is largely the direct or indirect consequence of marital breakdown . " His views are echoed by the eminent criminologists Michael Gottfredson and Travis Hirschi , who have written that " such family measures as the percentage of the population divorced , the percentage of households headed by women , and the percentage of unattached individuals in the community are among the most powerful predictors of crime rates . " Based on the research of another social scientist who was himself raised by a single mother , Bradford Wilcox , " boys living in single mother homes are almost twice as likely to end up delinquent compared to boys who enjoy good relationships with their father . " Moynihan said that " almost all school shooters come from families where the parents are either divorced or alienated " , and Cook argued that " perhaps they would n't need more gun control if they had better divorce control . " Some people have considered whether media attention revolving around the perpetrators of mass shootings is a factor in sparking further incidents . In response to this , some in law enforcement have decided against naming mass shooting suspects in media-related events to avoid giving them notoriety
Columbine High School massacre
Columbine High School massacre
Mass shooting