When an adolescent develops a substance problem, we often hear parents say he was self-medicating his attention-deficit disorder, or his anxiety, or his depression, or his school problems, for that matter.

There is a strong belief in such self-medication, and research might show that it works for some people. But I think the important thing to know is that even if substance use starts as self-medication—if a teenager says, for instance, I’ve been using alcohol, I really liked it, it helps me cope with my ADHD symptoms or my depression—once he develops a substance use disorder that really interferes with his life, he has two problems.

One thing that we have clearly learned is that if you treat only one of the problems—you treat the ADHD or the depression—the substance abuse doesn’t go away. Treating the substance abuse doesn’t make the depression or the ADHD go away either. You need treatment for both.

And we know that substance use disorder and these other disorders travel together, more often than not. So the focus of my research for the last 15 years has been how to really integrate—seriously integrate—the treatment of mental health problems and substance use disorders. We know that if we refer kids to substance treatment and they have untreated ADHD or depression, they don’t do as well in substance treatment. And if you refer a kid to a depression or ADHD treatment and you don’t address the substance abuse, the mental health problems aren’t going to get better either. So we really need to do both.

Related: How to Talk to Your Teen About Substance Use