With three apparent suicides of people linked to the Parkland and Newtown school shootings in recent days, mental health experts have an urgent message to massacre survivors: Their lives, while forever altered, are still worth living.

Jeremy Richman — father of one of the 20 first-graders killed in Newtown, Connecticut, in 2012 — was found dead Monday in an apparent suicide. His death came days after two teenagers who were students at Marjory Stoneman Douglas High School in Parkland, Florida, during the 2018 massacre also apparently took their own lives.

Their deaths have put a spotlight on the emotional fallout for those who survive mass shootings.

Zach Cartaya, a survivor of the 1999 Columbine High School massacre, with Emma Gonzalez, who survived the school shooting in Parkland, Florida. Courtesy Zach Cartaya

Zach Cartaya, 37, was 17 when two schoolmates killed 12 students and a teacher at Columbine High School in 1999.

For years, he wrestled with anger and anxiety. It would manifest in outbursts during unexpected times: when he was stuck on a plane on the tarmac, in important business meetings, after a breakup.

He had avoided getting shot by hiding for hours in a small office off of his choir classroom with dozens of other students. Despite the emotional impact it had on him, he didn't seek any professional help for his mental health for almost a decade.

"I always thought: 'Who am I to complain? Yes, I was trapped in a room, yes, it was scary, yes, I saw horrible things. But who am I to complain when other kids are dead or trapped in a wheelchair for the rest of their lives?'" he said.

"There is no comparison between physical and invisible wounds. But if you let yourself go down that road, I think it leads you to a really ugly place," Cartaya said.

He realized later he was suffering from guilt that he had survived while others, both at Columbine and in later mass shootings such as the one at the Sandy Hook Elementary School in Newtown, had not.

He abused alcohol and at one point contemplated suicide. Then, eight years after Columbine, he started seeing a therapist.

"There is no comparison between physical and invisible wounds. But if you let yourself go down that road, I think it leads you to a really ugly place."

Few details were provided about the recent apparent suicides connected to Parkland and Newtown.

But there were indications that at least one was directly related to the lasting trauma from a shooting. Sydney Aiello, 19, who was at Stoneman Douglas during the Feb. 14, 2018, mass shooting that killed 14 students and three staff members, died by suicide last weekend; her mother said Aiello was struggling with survivor's guilt and post-traumatic stress disorder.

Cartaya said it's critical for people who have survived a mass shooting to know that what they are going through is normal, and that help is available. He works as the director of finance for the Rebels Project, a nonprofit started by survivors of the Columbine shooting, that connects survivors of mass tragedy and trauma.

"It's so easy to feel isolated after something like this," he said. "You don't have to be alone."

Experts say survivor's guilt is common, complex and often misunderstood. Well-intentioned friends and family who did not go through the traumatic event themselves may expect the survivor to feel grateful to be alive, while in reality, the individual is likely experiencing many other emotions, said licensed professional counselor Phyllis Alongi, former clinical director of the Society for the Prevention of Teen Suicide.

"It leaves questions of, 'How do I deal with something of this magnitude?' The body, the mind, the psyche is struggling to make sense of something that doesn't seem to make any sense," she said. "That's coupled with anxiety and negative intrusive thoughts of, 'Why me? What could I have done to have saved others?'"

For teens, an underdeveloped brain adds to the struggle

Those thoughts can be particularly challenging for teens, whose brains are not fully developed until their mid-20s.

"Their problem solving, perception, and coping skills are still immature and underdeveloped, so they're already at a disadvantage," Alongi said.

The degree to which survivor's guilt impacts someone's life may depend on the level of trauma they were exposed to, as well as any pre-existing vulnerabilities to depression and anxiety they had before the event, according to Christian Burgess, director of the Disaster Distress Helpline at the National Suicide Prevention Lifeline. The helpline is a 24/7 phone and text service that connects people with crisis counselors during or after a traumatic event and can be reached at 1-800-985-5990 or by texting TalkWithUs to 66746.

"The vast majority of people who survive natural or human-made disasters are going to experience a temporary distraught reaction, but particularly with support from their loved ones or others in their support networks, they're going to be able to bounce back fairly quickly," Burgess said.

"But if they have experienced similar events in the past, have other things going on in their lives or have a higher exposure to trauma during the disaster, they can be at risk for more serious mental health concerns," he added.

The experts urged parents of children who have lived through disturbing events to arm themselves with the knowledge about the warning signs of suicidal behaviors, such as a dramatic change in eating, sleeping or socializing habits, and to not be afraid to check in with their child.

"Be honest with your child. Say: 'Hey, I'm really uncomfortable having this conversation, but I need to ask you, have you ever felt suicidal? What would you do if you did? Do you have a trusted adult?'" Alongi said. She suggested parents read tips on how to have that conversation on the Society for the Prevention of Teen Suicide's website.

For Cartaya, the Columbine survivor, there are certain aspects of life that are still a challenge. He doesn't like to have his back to a door, in case he has to make a quick escape. The sound of fireworks on July 4 brings back memories of what he heard in school on that day 20 years ago. And it took him years to chip away at the survivor's guilt he felt.

But his life has purpose, and staying in touch with other survivors brings him comfort. The most meaningful part of his work is when he sees survivors convince one another that they should get mental health help so they don't have to struggle as much.

"You're not alone," he said. "You have to start living a new normal."

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.