What we know and don’t know about how mass trauma affects mental health

In March, three people connected to mass school shootings died by suicide, raising questions about the lingering effects of such trauma on a person’s mental health.

Two teenagers who survived the 2018 shooting at Marjory Stoneman Douglas High School in Parkland, Fla., took their own lives within days of each other. The father of a child killed in the 2012 Sandy Hook Elementary School shooting in Newtown, Conn., died by suicide a few days later.

Suicide can occur in clusters, especially among teens. But it’s too early to tell if these deaths are connected in any way, are related to having experienced similar mass traumas — or if they simply occurred close together by chance, says April Foreman. A psychologist in Baton Rouge, La., and board member of the American Association of Suicidology, Foreman is familiar with all three suicides. “These are really complicated events,” she says. (One thing they aren’t, some researchers say, is contagious; a person can’t catch suicide like a common cold.)

But the deaths do shine light on a question that researchers are trying hard to answer: How does being connected to a mass trauma event like a school shooting affect a person’s later risk for mental health problems and self-harm? 

Here’s what scientists know — and don’t know.

Who is most at risk for developing mental health problems following a mass shooting?  

What little is known about mental health problems following mass shootings largely stems from research efforts launched on college campuses where such shootings have occurred.

In 2008, a gunman opened fire at Northern Illinois University in DeKalb, killing five students and wounding 21 before taking his own life. By chance, researchers had already established a study there with women enrolled in an introductory psychology course to look at mental health problems related to sexual abuse.  

Of 691 surveyed, about 42 percent experienced some symptoms of post-traumatic stress shortly after the shooting, according to a 2014 study in Behavior Therapy.  That included feeling numb and disconnected and having trouble regulating emotions. In a follow-up survey more than eight months after the shooting with 588 of those women, those still experiencing symptoms had dropped to about 12 percent.

Exposure to previous trauma predicted a person’s likelihood of developing PTSD, the researchers found. Other studies have shown that preexisting depression and proximity — both physical closeness to the actual shooting and emotional closeness to victims — raise the risk of experiencing ongoing psychological problems.

Who is most at risk for self-harm, including suicide?

Most people who survive extreme trauma, whether that’s a mass shooting or some other abuse, don’t kill themselves, experts say. But exposure to violence does seem to increase suicidal thinking and, for some, the ability to act on those plans.

“When you’re exposed to that kind of violent loss, it breaks past that little barrier that most of us have that says ‘This isn’t how the world works’ or that life is sacred, ” says Amy Mezulis, an adolescent clinical psychologist at Seattle Pacific University.

Since the mid-2000s, suicide researchers have been looking at the factors that shift a person from thinking about suicide to actually carrying out the act (SN: 7/7/18, p. 12). One idea, dubbed the three-step theory, suggests that those who are able to act on suicidal thoughts have come to see violence as normal (through combat, a suicide of a loved one, self-harm or other means), are predisposed to handle higher levels of pain and have access to guns or other means to carry out their plans (SN Online: 3/9/18).

Such suicide theories are often used to explain higher rates of suicide among war veterans compared with the general population (SN: 12/29/15, p. 22). But they could also apply to those exposed to violence through mass shootings, says Michael Anestis, a suicidologist at the University of Southern Mississippi in Hattiesburg.

 Are teens at greater risk for self-harm following a mass shooting than adults?

It’s possible. The brain is still developing until the mid-20s and that could make teenagers and young adults more vulnerable to suicide, Mezulis says. Teens are more impulsive, they have a hard time envisioning a better future or the future at all, and they struggle to see how their death would affect their loved ones.

What drives clusters of suicides?

To probe that question, one team of sociologists has focused on a high-achieving and affluent community with the fictitious name of Poplar Groves (the community requested anonymity). Since 2005, at least 16 current or recent graduates of the local high school have killed themselves, with the suicides occurring in three distinct clusters. With about 2,000 students attending the high school at any given time, a normal rate would be about one student every 4.5 years.

People go through great lengths to make sense of suicides. And that tendency becomes stronger when the people who killed themselves don’t fit expectations, says Seth Abrutyn, a sociologist at the University of British Columbia in Vancouver.  That was the case in Poplar Groves: Many of the students who took their own lives were outgoing and social, got good grades and excelled at sports.

Interviews with close family and friends revealed that many students who killed themselves struggled with mental health problems. But teens outside that inner circle developed a different script, Abrutyn and his colleagues report March 29 in Society and Mental Health. That script said that the pressure to achieve put their friends over the edge.

That feeling of pressure applied to a lot of other students at the school. Now, students in Poplar Grove “could imagine why one would do it. They could imagine how one would do it,” says coauthor Anna Mueller, a sociologist the University of Chicago. And that could put them at risk for suicidal thinking and, potentially, action.

How do we help those most at risk?  

Frustratingly, researchers don’t really know, Mezulis says. “We have good data that describe the percentage of people who recover, [and] the percentage of people who develop post-traumatic stress. We don’t have a good idea of what we can do following a trauma to change those outcomes.”

Following a 2014 shooting at her university that killed one student and wounded two others, Mezulis sent a survey to the entire school community. Of the 359 who responded, those who rated themselves as being more resilient and having more gratitude showed lower rates of post-traumatic stress four months after the shooting, she reported in the January 2017 Psychological Trauma. 

In recent unpublished work, Mezulis looks at how people think about trauma after the event. Rumination, or mentally running through events over and over, is common following trauma. Such thoughts can be intrusive and interfere with everyday life. But people can also practice deliberate thinking — that is, taking the time to make sense of the event.  People prone to deliberate rumination were better able to convert their feelings about a traumatic experience into a phenomenon known as post-traumatic growth, Mezulis says.

In growth (which can co-occur with post-traumatic stress), people wrestle and then expand their worldviews. “Growth requires people to go to a place where they’ve never been before,” says Julie Cerel, a psychologist at the University of Kentucky in Lexington and president of the American Association of Suicidology, who was not involved in this study.

Mezulis’ findings could point to ways to develop coping interventions targeted at survivors of, or people connected to, mass shootings, such as helping people foster gratitude in their daily lives or practicing more mindful rumination.   

The shootings happened a while ago. Why are we seeing these suicides now?

It isn’t a coincidence that the Parkland suicides occurred just over a year after the shooting there, says Cerel. That’s when social support networks created in the wake of a trauma typically begin to break down and most people move on from the event, she says. But for those who remain stuck in their grief, continuing to provide long-term support for survivors of events of mass trauma remains crucial.

That can mean continued use of intervention programs, such as those developed specifically for schools that have experienced a trauma. One such program, called “After a Suicide,” is freely available, and includes information about how to talk about suicide without adding to trauma or increasing suicidal thinking among survivors.

Should everyone connected to a mass shooting receive mental help?

“The most common mental health outcome after exposure to a trauma is no mental health outcome,” Mezulis says. The majority of bystanders and loved ones will slowly move on with their lives. At least initially, giving people the space to grieve in a safe and supportive environment is often best course of action, she says.

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If you or someone you care about may be at risk of suicide, call the National Suicide Prevention Lifeline, a free, 24/7 service that offers support, information and local resources: 1-800-273-TALK (8255).