My house was overrun with people when I sat down to watch an advance copy of the National's new documentary, Mistaken for Strangers.

I live with five other people. At the time, someone's boyfriend was staying over. So were two friends from back home in Oregon—one was sleeping on the couch, and the other was holed up in my walk-in closet. None of them cared much about the National, their brooding indie rock, or the new documentary made by the ten-years-younger brother of the band's lead singer, Matt Berninger.

When I put the movie on in my living room, a few people were cooking dinner in the kitchen, another was writing his résumé, and a pair was in the shower together. After 15 minutes, they had all sat down to watch. By the time Mistaken for Strangers was over, the couch was full—a half-cooked meal was on the stove, and the couple from the shower were wrapped in towels, air-drying next to me.

I sat down to watch the movie because I love the National. But the reason my roommates got sucked in was Tom—the movie's director and Matt Berninger's little brother. Nobody is as vulnerable and real as Tom—he puts on display all the embarrassing stuff that the rest of us spend our lives trying to hide.

While Matt was drinking wine on stage in front of packed stadiums over the past decade, Tom was still living with their parents in Ohio. While Matt was opening for President Obama, Tom was making low-budget slasher movies with his friends. While Matt was releasing a string of critically acclaimed albums, Tom wasn't even listening. He liked Judas Priest.

Matt made sporadic attempts to stay in touch—like late-night phone calls from France—but the brothers lived in two separate worlds. In 2010, Matt wanted to reconnect, so he gave Tom a job on the band's European tour. The little brother would be like a personal assistant to the band members. Tom told Matt he was going to film a documentary about the National. But he made himself the star.

I could relate to the two brothers—Matt left home for college when Tom was nine. My own little brother, Larkin, was ten when I moved to New York City. After I finished Mistaken for Strangers, I drunk-dialed Larkin in Oregon and asked if he wanted to skip a week of middle school and help me interview Tom and Matt.

Two days later, I picked Larkin up at the airport and we went to sit down with the Berninger brothers. They gave Larkin advice on staying in touch after the older brother leaves home, how to pick up high school girls, and the importance of not giving a fuck.

VICE: Larkin was ten when I left for college. Matt left when you were that age, Tom. Was that hard on you?

Tom: Honestly, I didn't even register it at first. I mean, I guess I was sad.

Matt: It was harder on me than it was on you.

In what way?

Matt: Before I moved away, Tom was always a close confidante—somebody who would listen to me. It was fun to have someone that just look up to me. And then I went off to college and I was a small fish, and Tom wasn't around.

The other four guys in the National are all brothers. They had each other. When the band started touring, I would call Tom from random places and be really depressed. I maybe missed him more than he missed me.

Tom: I would never call Matt. He would always call me. He'd be overseas, and I'd think it was so cool that he was calling me from France or something. Little did I know that he was on a month-long tour, playing in crowds of five or ten people. He had to talk to me to get his mind off of playing in front of nobody. To feel like he was home.

What's it like for brothers reconnecting as adults?

Tom: I think once Larkin hits 20, you'll realize how different you've both become. You'll get back together, but the differences will really start to show. Around that time, I became my own person. I started liking metal.

Matt: I tried to get him to listen to the Smiths, and I think he started listening to AC/DC to spite me.

How was it for you, Matt, to see Tom grow into his own person?

Matt: When I asked Tom to come on tour, I wanted him to be what he was back then—a guy that would listen to me pontificate and vent. But he wasn't that. He wasn't that little kid anymore. He was an adult. He swam through the world with a completely different stroke than I did.

There was a lot of tension. I was trying to make him more buttoned-up because I am more buttoned-up. But I learned that I had to stop trying to shape him. I stopped trying to get him to listen to the Smiths, and I started listening to AC/DC a little bit.

After a while, I realized—thank God—that Tom's got a different way of being in the world. Thank God he's more buttoned down. Thank God he's less like me than I wanted him to be.

Larkin is very smart, but he's also super quiet.

Matt: That's the opposite of Tom. Tom's really loud and dumb.

Tom just doesn't give a fuck. Even in the movie, he's completely out there—completely himself, for better or for worse. Do you think that's a way Larkin should try to be?

Tom: My not giving a fuck is a fairly new discovery. It was in my late 20s, right before I started making this documentary, that I stopped caring. I stopped letting myself feel bad. I was suffering from a lot of depression. I was on all sorts of drugs—

Matt: [ _to Larkin_] He means antidepressants.

Tom: Right, not the good drugs.

Matt: That's terrible.

I blame Larkin's impending drug issues completely on you.

Tom: You guys are from Oregon—come on. Anyway, I just stopped caring about what people think of me. I made a mental note to stop feeling bad about myself. I still suffer from depression every day, but there was a shift—now I'm just going to act the way I want to act. I'm just going to say what I want to say.

I used to be afraid to fail. It paralyzed me. When I starting making this movie, I had a whole mess of footage. I didn't have a direction. But there was something there, and I refused to let myself feel bad. I turned the footage into something.

You have any advice for Larkin, Matt?

Matt: I don't think you should try to shape yourself into a different person. But conversely, you should push yourself to do things that you're nervous about. The biggest one is going up to the person you're attracted to and asking him or her out on a date. Honestly, that's the hardest thing in the world to do. Nobody's actually good at that. But you do it anyway. You have to do it anyway.

Larkin: OK.

Matt: Don't try to change yourself, but take chances. Don't worry about failing, or falling on your face. Don't be somebody you're not, but work hard and accept failure as another step forward.

You will get knocked down by a million things in the world, whether it's a girl in high school or a failed project. You'll get rejected nine times, but the tenth time you won't. And all those times you got knocked down helped you figure out how to stand up that tenth time.

Larkin: OK.

That's the brilliance of Mistaken for Strangers, Tom. You aren't afraid of showing your missteps or little failures. That vulnerability is what kept me so engrossed. It sucked in all my roommates, too. Even those who aren't fans of the band.

Matt: We've heard from a lot of therapists that the movie is being buzzed about in those circles. There are so many people that have so many insecurities, especially in relation to their family. This film is about all of that.

You're supposed to be 30 and know what you're doing. You're only 14, Larkin, but you might get to 30—or to my age, 43—and still feel lost. That's something about the film that I like. Everyone stays a little lost their whole lives.

You're not going to figure it all out. You're not going to put all the pieces together. But that's the fun of it.

Larkin: OK.

Tom: You will figure it out to a point, but there's still a giant unknown. That's just adulthood. I really found a voice with this film. It wasn't what I thought it was going to be. And it's scary—I still have to figure out what I'm going to do next. Becoming an adult is very weird.

Thanks for talking to us, guys. It's inspiring to see how your relationship as brothers has evolved as you've grown up, but you're still close.

Matt: Tom lives in my garage!

Tom: Hopefully not for much longer.

I'd love if Larkin moved in with me as an adult.

Matt: I'd rather have Larkin living with me, too. [ _Laughs_]

We can trade. Larkin, you're going to live in Matt's house now.

Larkin: OK.

Follow River Donaghey on Twitter.

Mistaken for Strangers will be in theaters, On Demand, and on iTunes today. You can find theater listings and links to digital downloads at the official website.