News Release 

Case studies suggest that 'red flag' laws play a role in preventing mass shootings

Embargoed News from Annals of Internal Medicine

American College of Physicians

Below please find summaries of new articles that will be published in the next issue of Annals of Internal Medicine. The summaries are not intended to substitute for the full articles as a source of information.

Case studies suggest that 'red flag' laws play a role in preventing mass shootings
Experts examine 21 cases in which extreme risk protection orders were used in response to threats of mass violence


URLs go live when the embargo lifts

Case studies of individuals threatening mass violence suggest that extreme risk protection orders (ERPOs), colloquially known as 'red flag' orders, may play a role in preventing mass shootings. An aggregate summary and individual histories for a preliminary series of 21 cases are published in Annals of Internal Medicine.

Nearly 80 percent of perpetrators of mass violence in public places make explicit threats or behave in a manner "indicative of their intent to carry out an attack." For example, the shooters in the infamous Parkland, Aurora, and Tucson events, among others, were known by family members, acquaintances, law enforcement, and in some cases, health care professionals, to be at high risk for violence. ERPOs provide a rapid, focused response when risk of imminent firearm violence is high. Studies suggest that these interventions are effective at preventing suicide, but their efficacy in preventing mass shootings is not known. To date, there have been only two reported cases of ERPO use in efforts to prevent mass shootings. California enacted the nation's first ERPO statue, which took effect in January 2016.

Researchers from the Violence Prevention Research Program at UC Davis School of Medicine sought to evaluate the California statute's implementation and effectiveness by reviewing court cases for persons subject to the orders. Of 414 cases, the authors received 159 and developed an aggregate summary and individual histories for a preliminary series of 21 cases. Their research showed that most subjects were male and non-Hispanic white and the mean age was 35. Most subjects made explicit threats and owned firearms. Four cases arose primarily in relation to medical or mental health conditions, and such conditions were noted in four others. Fifty-two firearms were recovered. The researchers conducted print, broadcast, and Internet media Google searches using the subjects' names and locations to determine if they were the perpetrators of any violent events from the date of the order. As of early August 2019, none of the threatened shootings had occurred, and no other homicides or suicides by persons subject to the orders were identified. According to the authors, these cases suggest that this urgent, individualized intervention has a role to play in efforts to prevent mass shootings, in healthcare settings and elsewhere. They believe that further research would be helpful in determining definitively the effectiveness of such orders.


All of the 21 cases are published with the report. This report and all content related to firearms is free to the public at

Note: For an embargoed PDF, please contact Lauren Evans at To interview the lead author, Garen J. Wintemute, MD, MPH, please contact Carole Gan at cfgan@UCDAVIS.EDU or 916-734-9047.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.