NICE, France — It has been four years since Helen Wilson’s friend died in her arms after gunmen stormed Paris’ Bataclan theater as part of coordinated terror attacks that killed 131 people across the city.

While her own bullet wounds have healed, her mental scars are still raw — part of a long healing process many terror victims say society often does not understand or sufficiently help with.

“I literally do not trust most of the people that I meet. I think that they’re all out to get me now. It’s a paranoia and it’s constant and it’s very difficult to just breathe,” Wilson told NBC News at a summit on victims of terrorism in Nice, France, in November. “I’ve had panic attacks in the grocery store because somebody brushed past me or bumped me and I had to leave everything and literally run out of the store.”

Most of the 400 victims of terror attacks who attended the summit, organized by the French Association for Victims of Terrorism, were from developed countries and lucky enough to have good medical care and at least some counseling — in contrast to countless victims of atrocities in Afghanistan, Syria and elsewhere.

Max Boon, from the Netherlands, lost his legs in a 2009 bombing in Jakarta, Indonesia. Mo Abbas

But even delegates from wealthier nations said help was still lacking, some complaining of feeling forgotten once media attention had moved on from the aftermath of an attack.

In the United States, for example, emergency workers have had to mount a high profile campaign to maintain funding to treat illnesses sustained during the recovery efforts of the Sept. 11, 2001, attacks in New York.

“The media focuses on immediate sensationalization but they then forget about it and move onto the next big story, not realizing or probably not caring that there’s a journey we’re going through and sometimes it’s very difficult,” said Thelma Stober, who lost a foot in a suicide bombing on London’s subway in 2005.

Underscoring the long-term damage faced by terror victims, the Bataclan death toll increased to 131 from 130 some two years after the attacks due to the suicide of a victim suffering from post-traumatic stress disorder.

An average of 21,000 people were killed annually in terrorist incidents in the decade to 2017, according to the University of Maryland’s Global Terrorism Database.

At the summit, some victims said they had only been offered a handful of counseling sessions or none at all, spurring the growth of associations and gatherings in which victims turn to one another for support.

“The only thing that is keeping us resilient right now is communication with other victims,” Andriy Bazelevsky told the summit. His brother was one of 86 people killed when a truck plowed through pedestrians in a 2016 terror attack in Nice, near the summit venue.

On stage, victims found it cathartic to describe their experiences.

One bereaved parent described living in a “bubble of emptiness, a hollowness touching every aspect of life.”

Another spoke of being underwater: “Every time you try to be happy, something plunges you under.”

Retired New York fire chief Joe Pfeifer was the first incident commander at the Sept. 11, 2001, attacks, who lost his firefighter brother Kevin when the World Trade Center's north tower collapsed. Mo Abbas

Joe Pfeifer, a retired fire chief and the first incident commander at the Sept. 11, 2001, attacks, lost his firefighter brother Kevin when the World Trade Center’s north tower collapsed.

“It’s important to tell a story because by verbalizing a story, it starts to make sense of all the pieces of the event,” he said.

“You’ll notice it in this congress, you don’t even have to say it in words. People know what we’ve gone through … There’s a special feeling of we’re in it together and we can make a difference moving forward.”

The United Nations launched a Victims of Terrorism program last year, recognizing that giving victims a voice not only helps them heal but could also prevent further attacks by humanizing the long-term damage caused by ideological violence.

“We talk about terrorism in very abstract terms, but when you see people who have been affected by terrorism, you understand or try and understand the kinds of issues that have affected them,” Denise Lifton of the U.N.’s Counter-Terrorism Implementation Task Force said.

“You hope this will reach people and may change their thinking if they’re going down a more radical path.”

Max Boon, a Dutchman who lost his legs in a 2009 bombing in Jakarta, Indonesia, has taken the idea a step further, co-founding an organization that arranges for terror victims and repentant terrorists to visit Indonesian schools.

“Terrorists try to dehumanize their victims as collateral damage and the stories of victims have the potential to rehumanize them,” he said.

“I was bombed by an 18-year young kid … and once I saw a video of him speaking about what he was about to do, I could only notice what a friendly young man he looked like and think how he would have maybe done things otherwise if we could have gotten to him.”

If you or someone you know is in crisis, call the National Suicide Prevention Lifeline at 800-273-8255, text HOME to 741741 or visit SpeakingOfSuicide.com/resources for additional resources.