Unexplainable - Diary of a teenage brain

Episode Date: December 8, 2025

What's going on in teens' heads? Scientists working on a country-wide study following thousands of young people have spent the last decade trying to answer that question. Guests: Raul Gonzalez Jr., psychology professor at Florida International University This series was made possible by support from the Annie E. Casey Foundation. Vox had full discretion over the content of this reporting. For show transcripts, go to ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/unxtranscripts⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ For more, go to ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/unexplainable⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ And please email us! ⁠⁠⁠⁠[e-mail]⁠⁠⁠⁠ We read every email. Support Unexplainable (and get ad-free episodes) by becoming a Vox Member today: ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/members⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ Thank you! Learn more about your ad choices. Visit podcastchoices.com/adchoices

Hey, I'm Matt Bouchelle, comedian, writer, and floating head you may or may not have seen on your FYP. And I'm starting a brand new podcast. Wait, don't swipe away. It's called, That Sounds Like a Lot. You know that feeling when you check your phone, read a few headlines and think, that sounds like a lot. I can't do this. Well, I can, and I'm going to get into it every Friday. You can watch on YouTube or listen wherever you get your podcast. I'm going to start by breaking down whatever insanity is happening in the world. And then I'll sit down with a comedian or actor or writer or, honestly, anyone who responds to my DMs. This is not the place to get the news, but it is a place to get the news. but it is a place to feel a little bit better about it.

That sounds like a lot. Coming May 1st, part of the Vox Media Podcast Network. All right, Julia, Julia Longoria, co-host of Unexplainable. Bird Pinkerton, here we are. Here we are. At the doorstep of my maternity leave, literally, it begins tomorrow. But before you go, you have one last story to tell me. One last story, yes.

And appropriately, it's about the youths. Come on. Hi. Hey. Nice to meet you. I'm Julia. This is a part of our team. Hi.

So I went to the FIU, the Florida International University Center for Children and Families. Hi. And I met with a researcher named Raul Gonzalez. These days when I meet people in person, I am a real conversation starter. I know. I'm like really pregnant. I'm very pregnant. You do not look at the stage that you're at.

Yeah, from what you told, it's keep telling me. It is true. It is true. So, yeah, I was immediately a fan of Raul Gonzalez. He could tell me I don't look that pregnant all day long. What is he research? So he is the head of the Miami chapter of a really fascinating national study about teen brains. I'm a professor of psychology, psychiatry, and immunology.

And my area of research over the last 20-plus years has focused. focused on risk factors and consequences for drug use and addiction. And for the last little over 10 years, my life has been fully dedicated to the Adolescent Brain Cognitive Development Study. The Adolescent Brain Cognitive Development Study, ABCD for short. I've ever seen the movie Boyhood? So it starts with a child actor and they film the same boy as he's growing up over the years. Sure. Yeah, the ABCD study is the boyhood of adolescent brain studies. They followed the same cohort of nearly 12,000 kids across the U.S. for almost a decade. The ABCD kids that were all been following are now entering college.

Wow. So the ABCD study was first born when the NIH asked an age-old question, are the kids all right? Or more specifically, if they end up, being not all right. Why? What are the risk factors that lead to substance abuse? This was a question that Raul was studying in his little corner of the field. But it was tricky. Sample sizes were small. There was this recognition that to really move the field forward and understand what is a risk factor as compared to a consequence of substance use, we really needed to start with a huge study that started with adolescents before they started experimenting or using drugs. So when he heard there was going to be a national study following thousands of kids across the country over the course of their entire childhoods, he was in.

It was going to be the study that anybody would ever want to do, but nobody would ever have the resources to do. Raul became the head of the Florida site, one of 21 sites across the nation. They recruited kids at around age nine, and over time, they'd take MRIs of their brains and ask all kinds of questions to kids and their parents about their lives. We can get a really great understanding of who they are, what their life is like, from how their brain works to what's their family situation like, their personality, mental health assessments. They're also looking at brain shapes. Neuroimaging data, brain structure, but also brain function.

We have them do tasks while they're in the scanner to see how their brain is functioning as they're trying to solve problems. It also collect to urine samples, hair samples. Talking about things we collect, you know, we also collect baby teeth. Really? Yes. Sounds kind of gross and weird, right, to have a baby teeth collection. But babies are really cool because they're like the barks of a tree. And they can tell us about exposure.

to all sorts of heavy metals and toxins from birth. Wow. We have genetics. We look at all sorts of different stress hormones. I mean, we can't get everything, but we try. Basically, this study was going to be an adolescent data treasure trove to end all treasure troves. We covered so many things that we thought were important as risk factors for substance use and addiction. So was that the main impetus?

is like, is substance use and addiction was the kind of... That's how it started, Julia, but it's been a wonderful, slippery slope. Once word got out to the field of adolescent brain research that the NIH was going to collect data from a huge national data set over the course of years, other researchers, not just substance abuse researchers, wanted in on it. More folks started wanting to chip in and add additional things to the protocol. Wanting to ask more questions.

and collect more data. We've been contributing to areas of sleep and mental health, screen time and mental health, physical activity in its role, risk factors for obesity. What is typical brain development in youth and adolescents? We don't know.

All right, let's pause here for a second. This is By the way, because Julia is out on her maternity leave now. But when she first told me about this study, it kind of boggled my mind. The idea that there has been this enormous science experiment running for a decade to figure out what's going on inside teens' heads.

It's kind of amazing to me. I feel like people have been trying to figure out teens for a long time. Why can't he act his age? With limited success. In years, they're young men, but sometimes in their behavior, They act like children? That's it.

And so I wanted to know more about what these ABCD researchers were finding, but I also wanted to understand how it all works. Because I couldn't help but think that, sure, teens can be the coolest and most articulate people you've ever met in your life, but they can also claim up completely, right, and tell you absolutely nothing. Like, it is sometimes hard to even, get a teen to show up to something to begin with, as Julia, in fact, experienced.

Okay, I am sitting in my car. After she met Raoul, Julia wanted to meet with one of the teens in this study. It is 1.10 p.m. on a Monday, and this teen told me that she would be here between 12.30 and 1. So maybe I'm getting a text message. What's that interference? No, that's not her. Listening to Julia waiting in her car, it really did make me wonder, how do you get 10,000 or so kids to show up and answer questions

or get their brain scanned year after year? How do you get them to talk to you about their lives, honestly? Still waiting. Fortunately, the teen did arrive, and Julia did get some answers to these questions. But we are going to have to wait just a little bit longer to hear them. Approximately the length of an ad break. Teenagers, am I right?

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Just be sure to leave room for dessert. Their mile high tea with all the little cakes and sandwiches is a showstopper. Go to virginatlantic.com to learn more. I'm Maria Sharpova, and I'm hosting a new podcast called Pretty Tough. Every week, I'm sitting down with trailblazing women at the top of their game to discuss ambition, work ethic, and the ups and downs that come on the path to achieving greatness. We'll dive into their stories and get valuable insights from top executives, actors, entrepreneurs, and other individuals who have inspired me so much in my own journey.

Follow Pretty Tough wherever you get your podcasts. I'm a Sted Hearnden, and this is America, actually. We're all talking to each other to see what did we do wrong? What did we not see? I'm in Washington, D.C. this week to interview Ruben Gallego. He's a Democratic senator from Arizona, and he's been thinking openly about running for higher office. But he's recently run into some hot water because of his connection to Congressman Eric Swalwell. I have to learn from this and I will learn from this.

But for me, it's not a 2028 question. It's about what it means to be a better first boss in my office and also a better senator to my constituents. This week on America actually, we asked Gallego about predatory behavior in Washington, his plans for immigration reform and more. So my name is Brianna. I am an artist, and I've been doing art since I was eight years old. Brianna is 18 years old. She has dark eyes, dark, long black hair. She's wearing a FIU T-shirt, where she'll be enrolling next semester to study art. I like to do painting, drawing, sometimes sculpting here and there, but I mostly work with the material called gouache. And yeah, yeah, I like to draw cars. Her dream is to someday design cars for a luxury car brand.

But also I would like to also work with more affordable brands for cars, so more people that don't have the luxurious money can also buy those cars that I created. Yeah. To make things easy, we met at her future alma mater, FIU, in the very same office where the ABCD study takes place. It feels a lot like a doctor's office, a little lobby to welcome people. They're playing soft gen. as there's a maze of rooms that feel like doctor exam rooms, some with a bunch of chairs

set up for interviews. There are snacks like mac and cheese and goldfish, stickers for prizes you can win. She remembers the original reason she joined the study was not exactly her choice at first. It was her mom's. My mom was really intrigued by it, how, like, she was intrigued by the concept of seeing my brain develop and, like, you know, like, how the adolescents develop. So she signed me up for it. She mostly remembers her mom coming home with a folder full of pamphlets.

And then she ended up here in this office. But the first session, I came here and they explained to me to a fifth grader, which was honestly really great experience. And I really continued with it because my mom, like, she wouldn't force something upon me. Like, it's something with my choice as well. As a nine-year-old, she remembers she liked the idea of learning about her own brain. She wasn't thrilled about the idea of the MRI at first. I was just scared of the feeling of not having to move

because in the MRI you can't really move, so you have to say so. But she was into the idea of winning some money. Participants do get compensated, and kids would win prizes. So she was in. One of the main things that sticks out in her memory are the games they play on the iPad,

like a memory game she played once. Or one that Raul had mentioned to me. He said these games are meant to have. help researchers assess how much different kids are willing to take big risks with prizes on the line. There's visuals and you're clicking on things and you're picking this versus that. And sometimes you pick here and you win some money and sometimes you lose some money. So it draws for sort of this reward-seeking behavior. Is it sort of like you're taking the pre-teens to a version of the casino?

You know, pretty much. I remember one time I won like $35, which was a lot. and I think the maximum that you could have won was like 40, so I was pretty happy. This brings us back to the original purpose of the study. The researchers wanted to assess risk-taking behavior of youths to see if there were risk factors that might lead to substance abuse down the road. I was wondering if Brianna had gotten any hints

that the researchers were trying to suss out if she'd made any questionable choices. She told me they've asked her a lot of different kinds of questions. over the last 10 or so years. Personal questions and also general questions about what I eat. How much she sleeps? How many times you drink caffeine? How much does she exercise? How many times I go to school?

How many times I use my phone? How many hours of the week do I use my phone? What does she use her phone for? And as she got older and it got more appropriate, they also started asking other questions. So they'd asked me like, oh, do you have a boyfriend? how long have you guys been together? She told me the most surprising question she got came early on.

They asked me if I smoked once, and I was like, I'm nine. And as she got older, it went more in depth of the drugs. So, like, different types of drugs, like edibles. And so they went more in depth of those, fentanyl and all of that. In depth of how, like, what were they asking? I don't remember the names. It's like really, like, really, like, like really intricate names of the different types of drugs.

Asking you if you had done them? Yeah, exactly. Or if you'd heard of them. Yeah, exactly. Or if I've done any of them. It was mostly that. This line of questioning was really fascinating to me. Because, sure, these kids are told all their answers are going to be confidential,

unless they say something concerning about endangering themselves or others. But still, what teen is going to willingly? admit to doing drugs to an adult on the record. Brianna told me she does not and has not done any drugs, and I do believe her. Nothing serious with alcohol or drugs or anything like that. I know my parents saw me well to not play with that, and so I've always respected that. Do you think if you were smoking, you would have told the truth? Honestly, I don't know. It depends if I would tell my mom or not. If I didn't tell it, then I wouldn't say the truth.

But if I did, then, yeah, I would have said it. But yeah, no. Didn't this seem like a real flaw in the study? I posed that question to Raul. That is a great question. And I actually have some answers for this. Yeah? Sink your teeth in truth.

Okay, cool. Do we have evidence that everybody's telling us the truth? We have evidence that everybody is not telling us the truth. And that's not unique to this particular study. But we have some things to try to assess, measure, and control for this. So a subset of our – we collect hair samples from all our participants that we're able to collect hair samples from. There's money to sample some of them. So we do hair toxicology testing for presence of drugs in the hair, which is a very reliable way and can capture it quite a while back.

About 10% of our participants have had positive hair toxicology results but reported no year. use. 10% are liars. It's, you know, or they may be waiting to tell us the truth, right? That's a nice way to put it. All right. Bird again. So, the answer to the question, how do you get answers from teens, is you ask them questions,

but you also test their hair. You have them play games with some prize money on the line. You scan their brains to see if there are any answers hiding. out and there, right? The next thing I wanted to know, though, was what researchers working on this giant science experiment had actually figured out. It turns out a fair amount. There have been over 1,400 papers published so far on teens' relationship to caffeine and sleep and gaming, on the effects of family conflict and puberty timing, all kinds of interesting stuff. I called Raoul to learn a little bit more about his part of things, so the questions of drug use and addiction. And he says,

they're still waiting on some of the most interesting data, because the kids are in their late teens now, so 18, 19, 20. But it'll take a while for the data from their current lives to be cleaned up and ready to use. So he told me that researchers have spent their time so far, looking at the data coming in from the kids when they were tweens and early teens, up to about 16 or so. That's why a lot of the studies now, because of their age, are focusing on sipping, alcohol sipping behavior, vaping, puffs. Stuff that's not heavy substance use, but more like testing the waters.

Researchers working with ABCD study data can now look through everything that's been collected and see what might make someone more likely to have tried a substance. So, for example, some researchers looked at. data from ABCD study 12-year-olds. Social demographic variables, psychosocial variables, things like religion, race, ethnicity, income, peer factors, parent factors, the family environment, hormones, cognitive functioning, and then also structural brain imaging. And what they found, in this study at least, was that the psychosocial factors and the kind

of family variables were better or like more useful predictors of trying to, you know, substances than the brain structure stuff. Not that the neuroimaging is meaningless or we're not learning more about the brain and how it works, but its explanatory value in predicting future behavior is not as strong as some other factors that we're measuring. Now, another study did find that brain function scans might be more useful for predicting early substance use. But all brain scans aside, if you're thinking,

is it a big deal to try a substance? It's a fair question, right? Raoul is not saying that trying a single puff of weed or a single sip of beer or even a whole beer is going to doom you to a life of substance abuse.

Oh, no, absolutely not. Most people who have a full drink do not develop an alcohol use disorder. The vast majority of people that smoke a joint or consume cannabis do not develop a cannabis use disorder. But this data about early substance use should be helpful to the researchers when they finally get their eyes on the data they're collecting now from older teenagers. This period is when Raoul says we tend to see more heavy drug use start and more problems with drug use. Folks are starting to become independent. They're starting to start their own lives.

So being able to continue following the youth into their 20s and seeing where they go, what they do, how they're functioning in the real world, once the training wheels come off, is going to be incredibly valuable data. Raoul's hope here is that if they comb through enough variables, enough brain scans and genetic data points and questions about sleep, basically if they do a good enough job of peering into kids' heads,

then down the line, it could lead to a kind of roadmap for navigating the risky behaviors that so many teens engage in, a map that could help them see where teens tend to take wrong turns so they can help figure out what interventions might be effective. Like, let's say that the study had some kids who had very similar lives, right? They had a similar friend network, similar background, but some of them slept six hours a night, and some of them slept eight hours a night. If the data showed that the kids who slept more tended to have fewer problems with alcohol, then maybe for kids with this kind of profile, getting more sleep could be an effective intervention. That's exactly right. And we can even go one step further.

We could then even say, what were some of the things that are contributing to poor sleep? We might find that more screen time, less physical activity. We can start working our way backwards to try to disentangle the associations among these, variables. Again, at the end of the day, the hope for Raoul and his colleagues is that what they've learned from the ABCD study will help teens out in the world. In his conversations with Julia, though, Raul mentioned that he has a personal stake in trying to understand the teenage brain. You have a 16-year-old. I do. How is that going? I'm loving it. I feel like I hit the jackpot with her. She's got great judgment, but she's a teenager. And I see her now.

approaching all of these things that we often as adults refer to as risky behaviors. Stuff that he might want us to hear clear of, but stuff that also might be fine, or at least normal. Meaning that a significant proportion, if not half, or maybe even more than half, of other teens also engaged in similar behaviors. How much should Raoul worry if his teenager tries a sip of alcohol, right? Or even a whole drink. Like so many parents of so many teens before him, he has to try and figure out what's kind of dumb, but ultimately maybe fine for his daughter to do, and what is too risky and might lead to serious problems for her someday. When I called him up, I asked him if he struggles watching her make potential mistakes. Oh, well, yes, I mean, I think I struggle like any parent, but boy, I sure want her to make plenty of. of mistakes while I'm still around, and I can still kind of catch her before she falls, or let her

fall and experience natural consequences from mistakes and learn. Mistakes are opportunities to learn. So I cannot stop my daughter from engaging in risky behaviors. And then also, you know, why would I? Risk is an inherent part of the human condition. What I can do is try to mitigate the risks and hope that in the face of risk, we can still get great outcomes. And obviously she's she's a few years behind the cohort here, but she's close enough to them that you can't, you know, you don't have all of the data right now that you would hope to

have in like a decade. And even if I did, Bird, I wouldn't know how to apply it to an individual, right? You know, like, like, like, for her specifically, I would have to, that would be the art of parenting, right? But you don't, you don't feel like if you rated a decade, you would have, like a perfect roadmap or something to... I think I'd have a better roadmap. I don't know if I'd have a perfect roadmap. There's too much serendipity involved. But I do hope we can get better at understanding these various paths.

So there are things, this is good for like general policies, public health. These are things that can move the health of an entire population. But then applying some of these group level findings to the individual, you're better off than being uninformed, but it may not work out exactly how it worked out in the paper for the group for that one kid. But now, you know, apply it over thousands of kids and then, you know, it's different. And see what happens. If you want to learn more about the ABCD study and its findings,

we will link to their website in the transcript. If you want to learn more about developing brains, stick around, because this is actually the first in a. two-episode series about teen brains. This week, we talked about what we're learning about teen brains. Next week, we'll talk about what we might learn from them. Until then, this episode was reported by Julia Longoria, with some help for me, Bird Pinkerton, and it was produced by Julia and by me. Julia, we're all sending our love to both you and your baby. This episode was edited by Sarah Kate Kramer, Jorge Just, Joanna Solotaroff, and Meredith Hadnott.

helped keep this project running smoothly with all kinds of guidance, and Joanna is running the show. Christian Ayala did the mixing and the sound design. Noam Hassanfeld wrote the music. Kim Slaughterback checked our facts. Sally Helm and Amy Padula are the fact that some birds can see ultraviolet light. And I am always, always, always grateful to Brian Resnick for co-founding the show with me and with Noam. Thanks also this week to Badr Tarani for his time. And this year, series was made possible by support from the Annie E. Casey Foundation. If you have thoughts about this episode, if you've got thoughts about teen brains, say, or if you're participating in a longitudinal study that you think we should know about, please don't hesitate to reach out at unexplainable

at vox.com. We'd love to hear from you. If you'd like to support the show and the journalism that Vox does, we would love it if you would become a member. This holiday season, your membership actually goes further when you join Vox as an annual member, we will gift a complimentary membership to a reader facing financial barriers. You can read more about all of this at Vox.com slash members. If you can't join our membership for whatever reason, it would also mean a lot if you would leave us a nice review on your podcast platform, five stars, or a written review, that'd be nice to, or just tell someone in your life that they might want to listen to the show, Those things make a real difference.

Unexplanable is part of the Vox Media Podcast Network, and we will be back on Wednesday. It was another episode about Teen Brains.