RICHMOND, Va. (WRIC) — Social isolation may be one of the most important indicators in spotting a potential mass shooter, according to a new study conducted at Virginia Commonwealth University.

This study, which was originally published in December 2022, looked the behavior of 177 mass shooters and found that social isolation was the most important external indicator leading up to mass shooting. The results also showed that isolation can also be tied to other key indicators, like mood swings.

According to Dr. Nicholas Thomson, Ph.D., director of research and a forensic psychologist at the Injury and Violence Prevention Program and co-author of the study, the study is unique because it looked at behaviors that friends, family and co-workers of mass shooters can observe. This means that people can intervene or report concerning behavior early on.

“In many ways, this is the data that we need because others’ perceptions are integral to identifying and reporting at-risk individuals, and the community is critical to preventing violence,” Thompson said. “Equipped with the right knowledge we can develop risk awareness strategies that can prevent mass shootings from occurring. Of course, this is only one piece of the puzzle, but it is an important piece.”

According to this new research, social isolation is also typically noticed months or years before an attack. This is in contrast to other behaviors, like stocking guns and ammunition, which may not appear until weeks or days before an attack.

Because this behavior can appear early, this offers friends and acquaintances more time to intervene. This is something that Dr. Samuel West, Ph.D., assistant professor of psychology at Virginia State University and co-author of the study, says can happen on both a societal and individual level.

“Although most people who experience isolation do not go on to commit such acts of violence, intervening on that isolation only holds benefits for the individual,” West, who received his doctorate from the Department of Psychology at VCU, said. “This can be as simple as a friend stopping by in person to say hello and catch up — something that we could all benefit from.”

The complete study, “Exploring Personal Crises Observed in Mass Shooters as Targets for Detection and Intervention Using Psychometric Network Analysis,” will be published in a upcoming issue of the journal Psychology of Violence.