Injury due to interpersonal violence is a public health issue and should be approached with preventative medicine strategies, akin to modern approaches to heart disease and malignancy, as all similarly pose a significant public health burden. As care to the injured is refined and subsequent mortality rates decrease, prevention becomes of primary importance in extending these gains. Identification, implementation, validation, and dissemination of novel strategies to reduce interpersonal violence will lead to improved well-being of the general public and a healthier environment for all communities.

In 2013, there were 33,636 deaths related to firearm violence in the United States. Between 2012 and 2014, there were 1,860 homicides in Los Angeles County. Of those, 1,349 (72.5 %) were due to firearms. The recognition of gun violence as a health problem is the foundation to the implementation of preventative medicine techniques. An analysis of 753 consecutive deaths at a level I center reveals that 13 % were potentially preventable with changes in treatment. However, greater than 50 % of these deaths may have been avoided with preventative measures, such as reductions in alcohol use, the use of restraints, and helmets. Victims of violent assault are prime focus for preventative intervention due to their high rates of repeat injury, and in penetrating trauma, recidivism is of particular concern. Victims of penetrating trauma were more likely to suffer from gun violence again, where the risk of mortality increases by a factor of two for each subsequent visit.

Primary prevention measures seek to avert disability and disease (immunizations, fluorination of water, and vehicle restraint laws) and promote general good health (education campaigns for regular exercise and smoking cessation). These programs are intended for a wide dissemination to the general population. In contrast, the main objectives of secondary prevention are detection of disease at its earliest stages and before symptoms are grossly manifest. Examples include mammography, colonoscopy, and cervical exams. Early treatment can also take place in conjunction with these screening measures. An important but difficult objective of secondary prevention measures is to identify and preferentially target populations at risk, thereby maximizing the cost-effectiveness of screening efforts. Identification of these groups also grants an early opportunity to intervene and potentially modify risk factors, thereby reducing the incidence of disease. However, reliable identification of these groups can be complex. Tertiary prevention activities are intended to improve quality of life, reduce the severity or progression of symptoms, and if needed provide rehabilitation after disease has been diagnosed. This phase is generally considered a part of treatment.

On March 30, 1981, John Hinckley Jr., having access to a particularly lethal type of munition, attempted to assassinate President Ronald Reagan outside the Park Central Hotel in Washington DC wherein Press Secretary James Brady sustained a severe traumatic brain injury. On November 30, 1993, President Clinton signed the Brady Bill restricting firearm purchases in states that did not have more stringent restrictions already in place to include the more lethal type bullets used in the attack. This bill, and others like it, represents an example of primary prevention. Similar measures include denial of firearm purchase for those with felony convictions, age restrictions, mandatory waiting periods, strict registration and licensing requirements, concealed weapon legislation, and zero tolerance for firearms at schools. Multiple series have linked the availability of firearms, with a significantly higher rate of firearm assaults, and it stands to reason that laws restricting access would demonstrate decreases in the rates of associated injury and mortality. Indeed, data suggests that restrictive legislation decreases the incidence of handgun-related violence, particularly suicides, and the effect seems to be more pronounced when high-risk individuals are refused purchase. And further, regardless of the manner of procurement, storage, type, or number of weapons, the presence of a firearm in a home significantly increases the risk of homicide or suicide in that dwelling. However, data is mixed. There is insufficient evidence that these measures decrease violent firearms-related deaths overall. This lack of effect may be with reason as legislators are reluctant to divert public funds to specifically restrict gun control across the wider spectrum. For example, in 1996, the US House of Representatives added the injunction: “none of the funds made available for injury prevention and control at the Centers for Disease Control and Prevention may be used to advocate or promote gun control” to the final budget appropriation for the Centers for Disease Control and Prevention. Additionally, after the National Institute on Alcohol Abuse and Alcoholism funded a study linking gun ownership to an increased risk of firearm assault, similar restrictive clauses were applied to all Department of Health and Human Services agencies, including the National Institutes of Health. Despite this, data after passage of the Brady Act appears to show a benefit in firearm homicide and suicide rates in certain groups (i.e., age ≥55 years) but not uniformly across all demographics. Even so, these legislative measures do generally relate to decreased incidence of violent handgun acts to varying degrees and continue to be considered effective primary prevention in many communities.

Firearm buyback and exchange programs are thought to decrease the firearm density in high-risk areas and thereby decrease the incidence of violent crime. The media heavy aspect of these events produces visually effective messages, but, like the impact of handgun legislation, the results of buyback programs are inconclusive at best. Buyback weapons tend to be older or nonfunctional, small caliber and of the revolver type, whereas firearms used in crimes tend to be newer and semiautomatic. In a series of persons relinquishing firearms, almost 50 % reported the reason for participation being to prevent a child from finding the firearm and less so for reducing the likelihood that the weapon will be used in a crime. Further, 60 % of individuals relinquishing a firearm continued to be gun owners and 23 % of surrendered weapons were nonfunctional. Additionally, those who remained gun owners were just as likely as the national average to keep a loaded gun in the house or carry the weapon with them. Despite these results, buyback programs are considered a highly visible form of prevention and may benefit communities by bringing the issue of firearm density and gun control to wider public awareness.

An area for expansion of secondary prevention efforts is the retail sale of firearms. In a study tracing guns used in violent crimes, researchers found that gun retailers with a high rate of denied sales also have a higher rate of sales for guns that go on to be used in violent crime. The authors’ conclusions were twofold: (1) laws screening potential firearm buyers prior to sale do identify and deny sales to high-risk individuals, and (2) making these programs more restrictive might significantly decrease the legal sale of firearms to individuals who would use them in commission of a crime. With the seemingly greater incidence of mass shootings, this discussion of supply side restrictions is renewed. Two years after the Sandy Hook shootings, where 20 children and 6 adults perished, there remains strong public desire (gun owners and non-gun owners alike) to establish and maintain tighter restrictions and more vigorous tracking of purchases. In a study of gun violence involving juveniles (perpetrators and victims) in the Oakland, CA area, only 55 % of weapons could be traced to a dealer and only 39 % could be traced to an owner. The authors noted the need for more comprehensive tracing programs, where changes in ownership are registered with the federal government and stolen weapons are mandatorily reported.

The massacre at Columbine High School in Littleton, Colorado, where 15 people died and another 23 were injured, ushered in a new era of awareness of mass shootings in the United States. School programs are designed to intervene in high-risk groups in hopes of reducing violence. Secondary prevention of violent assault is often difficult, since interventions must identify those at risk while avoiding insensitivity and stereotyping with minimal disruptions to learning. The effects of these programs are variable. In a review of randomized controlled trials of school-based prevention programs, there were a decrease in violent behavior but no direct assessment of violent injury. In another study of similar programs, there was little effect on rates of aggressive behaviors or missed classes due to violence or fear of violence. The Youth ALIVE! Project, started in Oakland, California, seeks to intervene in high-risk schools through the “Teens on Target” program. This advocacy group trains peer educators to interact with disenfranchised students to provide coping skills and other assistance as needed. These programs have demonstrated a host of positive outcomes, including increased graduation rates among participants compared to controls. They also work with community leaders to facilitate related legislation. Notable is their involvement with Oakland’s gun tracing project, which is related to significant improvements over the prior system.

Trauma recidivism is the primary focus of tertiary prevention of gun violence. Recidivism can be as high as 50 % in some series and is of particular importance since patients experience significant increases in mortality with each re-injury due to penetrating mechanisms. Risk factors for re-injury are substance abuse (especially alcohol), mental illness, urban habitation, male gender, homelessness, and history of perpetration of or victimization by a violent act. Caught in the Crossfire (CinC) is another advocacy program active within the Youth ALIVE! organization. In an attempt to decrease retaliatory violence, this group has trained “intervention specialists.” These individuals have previously been victims of violent crimes and advocate for young victims of assaults. The first contact is typically during initial hospitalization. Clients are provided with assistance for themselves and their families. This includes help applying for victim-of-violence restitution funds, assistance with medical costs, job/school placement services, referral to mental health treatment, and transportation to court appointments. In a recent series, there were no readmissions and 50 % of clients who were not enrolled in school began or returned to coursework. However, while participants in these types of intervention programs tended to demonstrate a significantly decreased incidence of criminal involvement of any type, there was no difference in recidivism rates or mortality, even in prospective randomized trials. The growth of these hospital-based programs has led to The National Network of Hospital-based Violence Intervention Programs having representation in over 15 states in the USA and internationally.

Intimate partner violence (IPV) causes over 1,300 deaths and 2 million injuries per year and represents another avenue for potential prevention programs specifically as it relates to recidivism. Thirty-three percent of fatalities from IPV were previously victims of IPV, and there is a 20 % 5-year mortality rate after repeat attacks. Therefore, it is a priority to develop hospital-based programs for identification and intervention of potential victims. A combination of risk identification and legal measures seemed to be most beneficial. In a program of IPV intervention, substance abuse in the perpetrator generally trended toward higher re-injury in the victim. Additionally, victims seeking legal action against perpetrators were statistically less likely to experience re-injury, but, unfortunately, this did not result in decreased in re-injury in general or perpetrator incarcerations.