Sydney Aiello, a student who survived the Marjory Stoneman Douglas High School shooting in Parkland, Florida, and graduated last year took her life over the weekend, officials said.
She was 19.
Aiello had been close friends with Meadow Pollack, one of the victims of the Feb. 14, 2018, mass shooting at the school that left 14 students and three staff members dead.
"Beautiful Sydney with such a bright future was taken from us way too soon," Pollack's brother, Hunter, wrote on Twitter.
Aiello died from a gunshot wound to the head, according to Heather A. Gálvez, with the Broward County Medical Examiner's Office.
"The death of Sydney Aiello is tragic, shocking and heartbreaking, and surely at least in significant part the result of the ripple effect of the MSD shooting," a statement from Pollack's family said.
A GoFundMe account set up for Aiello's family said the teenager's passions were cheerleading, yoga "and brightening up the days of others."
Aiello, who graduated from Stoneman Douglas in 2018, was intending to go into the medical field, the site said.
But her mother, Cara, told CBS Miami that her daughter was struggling with her college classes because classrooms now scared her.
Cara Aiello said her daughter suffered from survivor's guilt and had recently been diagnosed with post-traumatic stress disorder.
Dr. Victor Schwartz, chief medical officer at The Jed Foundation, a nonprofit that focuses on monitoring teenagers' and young adults' emotional health and preventing suicide, said that "exposure to death around you does to some small degree raise the risk of suicide."
"It stands to reason that there is some increased risk around the survivor guilt," he said.
"Parkland students have done an incredible job being out there and advocating for gun safety, but the sadness and distress are still there. I’m sure many of these students are still struggling with symptoms that look like PTSD," he said. "And how could they not be?"
He added that changes, like going off to college or getting jobs, as many Stoneman Douglas survivors are facing, can be especially challenging for young adults who have gone through trauma.
"They and their families and support systems need to be aware of potential risk times," such as transitional periods, family illnesses and anniversaries of the tragedy, he said.
Cindy Arenberg Seltzer, the president and CEO of the Children's Services Council of Broward County, told NBC News that "a great deal of trauma services have been made available" to Stoneman Douglas survivors.
Seltzer said the variety of resources, through both the school district and outside agencies, have in some cases made it difficult for victims to know exactly where to turn to, but information can be found through Broward 211.
In an effort to further help the community after the shooting, Seltzer said, the Children Services Council also recently announced Eagle's Haven, a wellness center geared specifically toward Stoneman Douglas students, faculty and parents.
Schwartz said that those close to people who have experienced trauma should keep an eye out for sleep and concentration issues, erratic moods, increased despair, compulsive habits and substance use.
Loved ones should monitor victims and encourage them to seek help but be careful not to treat them like "walking time bombs," he said.
"You want to be a little bit more vigilant about what they're feeling and what their moods are and how they're functioning," Schwartz advised. "That just makes sense."