Ninety percent of people who are addicted to drugs started using them as teenagers. Most people with substance use problems also suffer with a co-occurring mental illness. And anywhere from 60 percent to 90 percent of teens who have a mental illness aren’t getting treated.

So if we ever want to stop the spread of drug addiction, we have to get serious about early intervention and mental health care for teens.

“Lost,” the newspaper’s 10-part series that concluded Tuesday, shows how challenges early in life can cause lasting damage. Look at the profiles of some of the people who have died from opioids in Maine in the past two years: Ashley Rideout, who was sexually abused by her stepfather and developed depression and post-traumatic stress disorder. Matthew McCarthy, who struggled with obsessive-compulsive disorder and low self-esteem. Utopia Brooks, who spent time in foster care when her mother became addicted to OxyContin. Darrell Clapper, who dropped out of school after being targeted by bullies.

The best way to stop the overdose death toll from climbing is to prevent young people from ever seeking out these dangerous drugs, but classroom lectures about the risks and consequences they face won’t mitigate the emotional pain that makes them self-medicate. Young people who are vulnerable have to have consistent, individualized care and attention.

We can’t slow down the spread of addiction without expanding access to mental health services – so it’s unconscionable that Maine is making it harder, not easier, for at-risk kids to get the help they need.

For every 10 people who have a substance use disorder, six also have a mental illness. Why? The diseases involve similar regions of the brain; they share genetic factors, and each can be triggered by experiences such as stress or trauma, including physical or sexual abuse.

Most importantly, both diseases often begin in adolescence, when the brain is vulnerable to disruption as it develops and matures. Consider this: Of the young people age 12 to 17 who had a substance use disorder in 2014, 28.4 percent had also weathered a major depressive episode in the past year. Among their non-addicted peers, only 10 percent had experienced depression.

Both addiction and mental illness respond to treatment – including medication and counseling – but it has to start early so that the brain can be rewired before an individual gets stuck in self-defeating patterns.

It’s a bad time for Maine to forfeit federal funds that allow intervention to take place. However, that’s exactly what our state has done, according to a report out recently from the Maine Center for Economic Policy. Last year, when an average of one person a day died of an overdose in Maine, the state Department of Health and Human Services failed to spend $800,000 in federal funds available to help adolescents struggling to overcome addiction.

Also in 2016, the DHHS left on the table an additional $3 million available from the U.S. government when it canceled, without explanation, a program that successfully provided wrap-around services to young adults who have or are at risk of developing a mental illness: coaching, care coordination, psychiatric treatment and peer mentoring. (Among the services affected was Portland Identification and Early Referral, which began at Maine Medical Center and has become a national model.)

The state didn’t even have to provide matching funds to access the federal money for these substance abuse and mental health programs, yet it was left behind anyway, ACLU of Maine director Alison Beyea said in a March 31 Maine Voices op-ed. The DHHS has failed some of Maine’s most vulnerable citizens, and all of us will pay the price.