At approximately 9:30 a.m. on Dec. 14, 2012, shortly after murdering his mother in the home they shared together, 20-year-old Adam Lanza entered Sandy Hook Elementary School in Newtown, Connecticut and opened fire, fatally shooting 20 children and six employees of the school before killing himself. All of the children were between 5 and 10 years old.

The Sandy Hook massacre ignited a national conversation about gun legislation and mental health care. Families of the Sandy Hook community immediately took action, forming nonprofits and educational programs to enact gun safety reform as well as programs for access to mental health care. This week, in part with the help of the families of Sandy Hook, Congress approved the 21st Century Cures Act, which has been widely heralded as one of the most significant achievements in mental health legislation in nearly a decade. According to NPR, the 21st Century Cures Act includes “provisions aimed at fighting the opioid epidemic, strengthens laws mandating parity for mental and physical health care and includes grants to increase the number of psychologists and psychiatrists, who are in short supply across the country.”

Nicole Hockley and Mark Barden both lost their 6-year-old sons in the shooting. Moved to action, Hockley and Barden co-founded the Sandy Hook Promise (SHP), a national nonprofit that focuses on preventing gun violence before it begins and a huge proponent of the 21st Century Cures Act. Through its educational “Know the Signs” program, as well as its legislative advocacy on both state and national levels, SHP works with children and adults to identify the warning signs of behavior associated with gun violence.

The Sandy Hook Promise recently launched a poignant PSA by BBDO New York titled “Evan,” which represented the chilling oversight of behaviors that can result in violence, as well as the importance of access to mental health care. The PSA captures the shock and tragedy of mass shootings by illustrating just how subtle the warning signs of gun violence can be. It has since amassed nearly 7 million views on YouTube.

Complex spoke with Hockley and Barden by phone to discuss “Evan,” gun violence in schools, and where they’re at on the four-year anniversary of Sandy Hook.

What was the intention behind releasing last week’s PSA?
Nicole: In terms of the video itself, we had been working on this concept for a couple of years, because our whole mission is to teach people to know the signs. These warning signs and signals are given off before someone can attack or harm against themselves or someone else. The evidence stacks up, and we teach people by going out and providing programs. We've trained nearly a million and a half people, but we've wanted to have a broader reach and educate people that this is available to them and that violence and gun violence is preventable when you know the signs.

What are some of the things that you discuss, some of the warning signs?
Nicole: We have programs that focus specifically on chronic social isolation and how to promote inclusion, and that's one of the signs we highlight in the video. We have programs that teach kids how to recognize overt threats or at-risk behaviors in social media and how to take action, and that's also highlighted in the video with the Instagram photo. We teach adults how to assess threats, and what the signs of an emerging mental health crisis are. We talk about other signs, such as antisocial behavior or being overly aggressive, or using intimidation or bullying tactics, something that we also see in the video. Or, an obsession with weapons or firearms, or an obsession with homicides or suicides.

You both lost children in the shooting. Can you describe to me your healing process and where you’re at four years later?
Nicole: I don't really know where I am on my healing process. What I do with Sandy Hook Promise and reaching out to save the lives of children and prevent other parents from experiencing the grief that I experience is my motivation and is the legacy I want to deliver for my child. I wouldn't say I'm healing, necessarily, but this is part of my way of— I guess you could say this is part of my way of healing, by helping others so that Dylan's death wasn't senseless, meaningless.

Mark: “I kind of go from one extreme to the other. Jackie, my wife, and I will sit at the table in the morning having coffee and still shake our heads like we can't believe this has happened. I know, for the rest of the world, this is almost four years ago, and for some it may be ancient history. But for us, we are still very much in a process of actually trying to get our heads wrapped around this and looking at the empty chair and still contemplating the fact that Daniel is really gone—and really gone forever.

On the other end of it, I’m kind of propelling myself through this time, through these four years, by distracting myself with trying to be the best dad I can for my surviving children, James and Natalie, and with being the best husband I can for my wife, Jackie, and then doing this intense work with Sandy Hook Promise. It's very hard—very fraught with setbacks—and then we have these stunning moments of encouragement. For me, there’s this whirlwind of extremes of ups and downs and continuous back and forth between the successes that we see here at the organization and then the tragedy that brought us here, and everything in between.

Are the families of the victims in touch?
Nicole: Oh, yeah. The community is fairly large. Not everyone else is, but Mark and I, and Jackie, Mark's wife, they are like extended family to me. I think of Mark as a brother. We lead the organization together. This is our family foundation, as it were. There are a couple of other members from the Newtown community. Those who lost loved ones, those whose children survived the shooting that I remain close with. And then there are survivors and victims’ families from other shootings, from Virginia Tech to Aurora to Columbine that I have contact with. There's a saying that this is all part of the club that no one wants to belong to, and that is true. One common thing that a lot of us share is the desire to prevent these tragedies from happening.

Does Sandy Hook Promise take a formal position on gun control or legislative reform?
Nicole: The majority of what we do is focused on the educational side. We're on the programmatic change, teaching people how to recognize the signs, because that's all part of preventing gun violence before it happens. We do also have an advocates arm. We don't advocate for gun control. We advocate for gun safety, so around appropriate access and around policies such as the restraining order that complements our "Know the Signs" program, because once you then know the signs, there is a process by which you can temporarily remove any lethal weapons from that person or restrict them from purchasing the weapon until they are no longer at risk.

We also support mental health and wellness legislation, and one of the big, big dreams we had [came to fruition] recently. We've been working on the Mental Health Reform Act for nearly four years now, since around spring or early summer of 2013. Last week, it passed in the House almost unanimously, and then it passed in the Senate at a vote of 94 to 5, again, almost unanimously. Now, it's going to be signed into law. That's a major victory, and that's one of the major mental health policies passed in at least a decade and one of the biggest healthcare components in our country since Obamacare. So that's going to help a lot of people in terms of suicide prevention, services for people who need mental health services, and a lot of other things, and that helps with gun violence prevention as well.

Mark: The Mental Health Reform Act is part of a larger package of health care reform called the 21st Century Cures Act, which addresses a whole lot of other issues in a positive way. It was going into opioid addiction and suicide prevention and all kinds of great stuff in that larger package, but we focused primarily on the Mental Health Reform Act of 2016.

It's been a good lift for us, I'd say, as we head into this very difficult time.