[5] Rates of violent deaths by firearm range from as low as 0.03 and 0.04 per 100,000 population in Singapore and Japan, to 59 and 67 per 100,000 in Honduras and Venezuela.
[6] The highest rates of violent deaths by firearm in the world occur in low-income South and Central American countries such as Honduras, Venezuela, Colombia, El Salvador, Guatemala, Brazil and Jamaica.
[15] According to the Huffington Post, FBI data shows that gun-related violence is linked to gun ownership and is not a function or byproduct of crime.
FBI research shows that between 2000 and 2013, "In 5 incidents (3.1%), the shooting ended after armed individuals who were not law enforcement personnel exchanged gunfire with the shooters.
"[18] Another proposal is to expand self defense laws for cases where a person is being aggressed upon, although "those policies have been linked to a 7 to 10% increase in homicides" (that is, shootings where self-defense cannot be claimed).
[27] A 2002 study found that access to guns in the home was associated with an increased risk of suicide among middle-aged and older adults, even after controlling for psychiatric illness.
[41] In contrast, a 2004 study led by Daniel Webster found that such laws were associated with slight reductions in suicide rates among children.
[42] A committee of the U.S. National Research Council said ecological studies on violence and firearms ownership provide contradictory evidence.
The committee wrote: "[Existing] research studies and data include a wealth of descriptive information on homicide, suicide, and firearms, but, because of the limitations of existing data and methods, do not credibly demonstrate a causal relationship between the ownership of firearms and the causes or prevention of criminal violence or suicide.
"[43] The United Nations Office on Drugs and Crime (UNODC) defines intentional homicide as "acts in which the perpetrator intended to cause death or serious injury by his or her actions."
This excludes deaths: related to conflicts (war); caused by recklessness or negligence; or justifiable, such as in self-defense or by law enforcement in the line of duty.
[25] Access to firearms is not the sole contributor to increased homicide rates, however, as one study by the Southern Criminal Justice Association in 2011 found.
In response to suggestions by some that homeowners would be wise to acquire firearms for protection from home invasions, Kellermann investigated in-home homicides in three cities over five years.
[61] Following the Sandy Hook Elementary School Shooting, accidental firearm deaths increased by about five hundred percent until April 2013.
[66] Even though there are about 14 million people with serious mental illness in the United States, they only take up a small portion of the perpetrator of mass shootings in the nation.
These causes, which tend to be created by other people, such as friends, relatives, acquaintances, and enemies, are much more likely to occur than a random spur of the moment killing.
It was determined in a study that for every firearm death in the United States for the year beginning 1 June 1992, an average of three firearm-related injuries were treated in hospital emergency departments.
[72] Children exposed to gun-related violence, whether they are victims, perpetrators, or witnesses, can experience negative psychological effects over the short and long terms.
[73] Psychologist James Garbarino, who studies children in the U.S. and internationally, found that individuals who experience violence are prone to mental and other health problems, such as post-traumatic stress disorder and sleep deprivation.
[74] It is conceivable that over a longer period, physical and emotional sequelae of mass shootings may lead to an array of symptoms and disability among affected individuals and communities who will likely experience lifelong consequences by carrying long-term memories of devastation, violence, injuries, and deaths.
On 15–16 December 2014, a lone gunman, Man Haron Monis, held hostage 17 customers and employees of a Lindt chocolate café.
[86] According to a report published by academic researchers in 2017, shooting incidents with fatal outcomes are about 4 to 5 times as common in Sweden compared to neighbouring countries such as Germany and Norway when taking population size into account.
The grave violence in the studied period also changed character, from criminal motorcycle gangs to city suburbs.
[91] A 2018 systematic review of 25 studies on firearm violence in Sweden by criminologist and physician Ardavan Khoshnood, concluded "that even though knives/sharp weapons continue to be the most common MO in a violent crime in Sweden, firearm-related violence is significantly increasing in the country and foremost when discussing gang-related crimes.
"[92] According to researcher Amir Rostami at Stockholm University, police statistics for January–November 2018 showed that the number of shootings was at a continued high rate at 274, where up until the end of November 42 people had been shot and killed and 129 wounded compared to 43 in 2017.
About half the shooting resulting in killings took place in so-called vulnerable areas and represented an increase on the preceding year.
[95][96] According to researcher Amir Rostami in 2021, those responsible for the gun violence are predominantly young men and often second generation immigrants.
[117] Approximately 1.4 million people have been killed using firearms in the U.S. between 1968 and 2011, equivalent to a top 10th largest U.S. city in 2016, falling between the populations of San Antonio and Dallas, Texas.
In a study, youth who reported mental distress were discovered to have a 68% higher chance of hurting others on school ground compared to youth who did not experience mental distress[133] On December 14, 2012, Adam Lanza shot and killed his mother at her home and then drove to Sandy Hook Elementary School, where he killed 20 children and six adult staff.
[134] The event reignited a debate regarding access to firearms by people with mental illness and gun laws in the United States.