What all parents can (and must) learn from Columbine

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Sue Klebold (right) was recently interviewed by Diane Sawyer of ABC News about the memoir the mother of Columbine High School shooter Dylan Klebold has written.AP

The Columbine High School massacre took place on April 20, 1999. Almost 17 years later, the mother of one of the shooters has finally written about her experience, and it's a cautionary tale that every parent needs to hear.

On Monday, Sue Klebold released the memoir "A Mother's Reckoning: Living in the Aftermath of Tragedy," in which she tells her side of the story. Klebold has already begun promoting the book, the profits from which she says will go to mental health-related charities. She appeared on "20/20" Friday night, sitting with Diane Sawyer for a courageous interview in which Klebold shared what she learned about herself and the mistakes she felt she made with her son Dylan, who is believed to have conspired with classmate Eric Harris to perpetrate the deadly attack.

It's never easy to look in the mirror as a parent, and wonder "if only." The likelihood of your child becoming a mass murderer is very low. But the likelihood that your child may struggle with depression, anxiety, anger, and low self-esteem is very, very high, and the "20/20" broadcast cited a report that 15 to 20 percent of all teens in the US contemplate suicide. These are the issues that Dylan apparently struggled with from puberty until his tragic end.

There are three major red flags Klebold cites that she either missed or minimized. First. Dylan began to isolate himself when he was home, and was mostly angry and full of attitude. She was aware that his grades and engagement in school were going downhill. This might have been a warning, but she assumed it was just the normal trajectory of the teen years, so she chose not to confront him and let him be. Concurrently, her older son was involved with drugs and she was distracted from Dylan as she was dealing with what felt like a more pressing and immediate crisis. If only. . .

Second. Dylan's behavior escalated when he was caught hacking into the school's computer system and found guilty of breaking into a van, stealing computer equipment. This could have been another red flag, but Klebold said she lectured, yelled at, and punished him by taking away privileges, never thinking that this might be symptomatic of some deeper issues. If only. . .

Third. Dylan's room. As was widely reported, Dylan's room was messy, chaotic, and when searched after the massacre, journals were found documenting his feelings of anger, insecurity, depression, murder, and suicide. Thinking that she should respect Dylan's privacy, and feeling that his room was his sacred place, Klebold never went in on her own accord. This seems like one of her most profound regrets. If only. . .

Like most teens, Dylan suffered from an array of powerful and confounding feelings. Contributing to this intensity is a developing teenage brain in which the amygdala, the emotional center of the brain, is in overdrive, and built to magnify these feelings.

Tips for keeping your teen emotionally safe

Your teen's bedroom: Your teen's bedroom holds many clues to their mental health. Privacy can be respected until your teen gives you cause to think otherwise. Changes in mood, behavior, and relationships merit examination. There is nothing more important than your teen's physical and emotional safety, even if it means violating privacy.

Teens who isolate: Teens who are engaged with their family do not want or need to spend all their at-home time locked away in their rooms. The more a teen isolates, the more parents tend to let them isolate. I get that it's no fun having to face a teen who wants nothing to do with you, but isolation is not a normal part of adolescence. If your teen won't come out, then you lovingly go in!

Your teen is engaging in uncharacteristic and risky behaviors: Be careful of using the "teens will be teens" defense when your teen engages in behaviors that worry you. If you see a pattern of rebelliousness, secrecy, and hostility, it's important not just to punish, but to look below the surface. Ask yourself questions, and look for areas in your teen's life that might be factors in motivating this behavior.

Be aware. Be present. Be available. Be the squeaky wheel. Your teen may roll their eyes, ignore you, or turn their back on you, but stay strong. Be patient, calm, and persistent. Most important, be proactive.

Give voice, acceptance, and understanding to those feelings you imagine might be troubling them. Teens feel the feelings but often can't articulate what exactly feels bad. Asking "What's wrong?" often results in the grunt of "NOTHING!" Instead, use your powers of observation as a starting point:

• You seem overwhelmed and stressed lately, can we help?

• You look angry and frustrated, how can we help?

• I've noticed you spend a lot of time alone in your room and look really down. I'm wondering if you're feeling pressure from us, from friends, from yourself. How can we help?

All teens experience various levels of anxiety, self-doubt, depression, and anger. Only when we as parents are able to confront our own denial and avoidance of these scary and uncomfortable places can we offer the validation and understanding necessary to help them navigate through these treacherous waters.