WASHINGTON — The FBI has helped to disrupt or prevent nearly 150 shootings and violent attacks this year, in part by steering potential gunmen toward mental health professionals.

There have been hundreds of these disruptions since 2011, Attorney General Eric Holder told an audience of police chiefs in October, touting the behind-the-scenes work of a small FBI unit based out of Quantico, Va. In most cases, the FBI has helped potential offenders get access to mental health care.

Preventing mass shootings through threat assessments and treatment is an unusual tactic for an agency known for its crime fighting and not for interventions. The achievement stands out during a time when President Barack Obama made curbing gun violence a priority for his administration, yet has had very little success. One year after the deadly mass shooting at a Connecticut elementary school, the White House’s biggest efforts to curb gun violence — attempts to reinstate the assault weapons ban and expand background checks for all gun purchases — failed without congressional support.

Mass shootings like the rampages in Newtown, Conn., the Washington, D.C., Navy Yard and the Aurora, Colo., movie theater do not represent the majority of gun violence. Yet when they do occur, the impact is high. And many times there’s the question of whether the shooter had adequate mental health treatment to prevent it from happening. Yet, in the national discourse about reducing gun violence, mental health treatment has received much less attention than banning assault weapons.

The FBI’s Behavioral Analysis Unit, for years, has been working with state and local authorities to profile potential offenders with the goal of preventing violent crimes like mass shootings. The “prevented” shootings and violent attacks from January through November of this year represent 148 cases that a division of that unit, the Behavioral Threat Assessment Center, has conferred on during 2013. And that number is up 33 percent from 2012, Andre Simmons, unit chief of the center, said in an interview with The Associated Press.