JUDY WOODRUFF: But, first, a new report looks at how digital devices are taking a toll on kids and families.

The report issued yesterday by Common Sense Media found half of all young people feel they are addicted to their devices. Almost 60 percent of adults think their kids are addicted too. And a third of parents and teens say that they argue daily about screen time.

Now a new documentary explores this topic and offers ideas about what families can do to navigate these waters.

William Brangham is back with our look.

WILLIAM BRANGHAM: The documentary is called "Screenagers," and, in it, Dr. Delaney Ruston explores the complex relationship teenagers have with their screens, both the pleasures they take in sharing their lives online with their friends, as well as the darker side, those who lose control of their digital habits, and spiral into damaging behavior.

WOMAN: When I went to hug him, I could feel the bones in his back. And that was scary.

WILLIAM BRANGHAM: The film also looks at the latest research about the impact all this screen time has on the brains of young people.

SHERRY TURKLE, Massachusetts Institute of Technology: You have a brain that is wired for what in psychology is called seeking behavior, the kind of thing that a Google search gives you, something new, something stimulating, something different.

WILLIAM BRANGHAM: Throughout the film, Ruston also turns the camera on herself, exploring the real and all-too-common conflicts that flare up as she and her family haggle over screen time.

DR. DELANEY RUSTON, Filmmaker, "Screenagers": What should the rules be? Because we don't have any right now.

TESSA RUSTON: I think the rules should be there is no rule. It's not like I'm on it 24/7.

DR. DELANEY RUSTON: When you have it, you're always checking it. And I — don't you think that…

TESSA RUSTON: Well, if you put this in front of me, yes, I will go on it, and, yes, I can find something to do on it.

DR. DELANEY RUSTON: Tessa, why are you so mad? OK. Just get dressed. I'm sorry you're crying.

WILLIAM BRANGHAM: I met with Delaney Ruston last week in Washington, D.C.

I wonder, what was that — initially, what made you want to do this film?

DR. DELANEY RUSTON: Well, I was having a really hard time as a mom with my two kids. You know, my son wanted to play video games a lot and my daughter really wanted more and more social media, and I felt completely out of control.

And, as a doctor, I was thinking, what is the impact of all this screen time? I knew, as a mom, that, every day, there was tension in the house, and I felt completely out of control on what to do, what kind of limits to set, how this was affecting them.

WILLIAM BRANGHAM: Now that you have done all this research, what was it, I'm curious, that most surprised you that you found?

DR. DELANEY RUSTON: Well, I think one thing that really helped me to start to be a better parent around this is to learn that the dopamine that's secreted in the brain's pleasure center when we get new bits of information and we look at the screens, that center of the brain is most activated when we're kids and we're teenagers.

So, knowing that they are so pulled into these in a way that we can't even understand has made me not be as angry at them, but realize there's a lot more I need to do as — in my parenting.

WILLIAM BRANGHAM: So, these are little electronic drug delivery devices? I know that's a crude way to put it, but that's what you're saying.

DR. DELANEY RUSTON: Absolutely.

I mean, it's amazing that there's many studies that look at MRI scans of the brain of kids who play a lot of video games, 20 hours or more of video games a week. And when they compare them to people who are addicted to, say, drugs or alcohol, their brains scans are similar. So, something is really happening on a physiological level. It's not just psychological.

MAN: We exposed young mice to switching sounds and light.

WILLIAM BRANGHAM: In the film, Ruston talks with researchers who are studying what multitasking, switching rapidly back and forth between digital devices, does to the brain function of mice.

MAN: Afterwards, we looked at the effect on learning and found that the ability of these young mice to learn new things was very much compromised.

It took them three times longer or more to learn how to go through a maze than the non-exposed young mice. We are exposing a whole generation of children to this rapid-paced media, and we have no clue what it does to the brain. And if it's the same as we see in the mice, then this is very shocking news.

WILLIAM BRANGHAM: I mean, does that kind of stuff terrify you? Or do you think this research is not necessarily analogous? I mean, how are people supposed to process this information?

DR. DELANEY RUSTON: You know, I think it's a question about how much we're giving kids full potential in everything that they do. And, to me, a big issue is how much time they have with all sorts of skills that they're learning offline, social engagement, competency, talking to people face to face.

So, I think, if we're giving them a lot of those situations, that even if there's some concern about attention span and possibly some changes in the brain, I think that humans are resilient enough — and already we're seeing that people are not, you know, dropping like flies from screen time. I don't think we're at that place yet where we need to be really alarmist.

WILLIAM BRANGHAM: Let's say I'm a parent and I come to you and I say, I have a young kid, maybe a 10-year-old daughter. When should I get her a phone? What would you tell this parent?

DR. DELANEY RUSTON: I think, you know, obviously, every kid is different, and that's really important. And every situation in the home is different.

But I do worry that it is getting younger and younger. And when we bring them — start having them in elementary school, we have to wonder, when is it too young that they're not going to be able to resist the impulse to check or to post?

MAN: Every girl in the picture is locked into her phone. Peralta knocks it into center. David tonight 2-2, a leadoff single here in the fourth, and nobody noticed.

We need to — can we do an intervention?

DR. DELANEY RUSTON: This is all about teaching kids self-control, and what we have learned through the research is that it's absolutely teachable. So, I would really discourage a family from getting a child a device when they don't feel like they are going to be able to control themselves from when they use it.

WILLIAM BRANGHAM: Ruston has been taking her film across the country recently, holding screenings in dozens of cities, encouraging parents and kids to come, to watch, and to then continue the conversation at home.

DR. DELANEY RUSTON: You know what I think is really exciting, is that kids and teenagers actually want to talk about these issues.

And I think that it doesn't take that long in homeroom or in some other setting to ask these questions about, what are you struggling with, with your screen time, or what do you see happening on social media? And once we say we want to hear from you, then they care, as opposed to what I see so often is this message of zero tolerance, let's just take everything away and get mad at you.

That's not going to get kids to open up and feel comfortable to be a part of this, and that's really what this is going to take.

WILLIAM BRANGHAM: For the "PBS NewsHour," I'm William Brangham in Washington, D.C.