“Heaven Knows What” is a movie which takes us into a landscape alien to many of us: the world of a drug addict. Arielle Holmes stars in a riveting performance as Harley, a homeless addict on the streets of New York who has two passionate yet volatile loves in her life: her boyfriend Ilya and heroin. We watch as they struggle to survive one day after another on the mean streets of New York, struggling with addiction and each other as Harley attempts to prove her love to Ilya in the most passionate and dangerous way possible.

The movie was directed by brother filmmakers Josh and Ben Safdie whose previous credits include the comedy drama “Daddy Longlegs,” the documentary “Lenny Cooke,” and the crime-drama “Good Time” starring Robert Pattinson. I got to speak with them while they were in Los Angeles, and they described the various elements behind this movie’s making in great detail.

“Heaven Knows What” is based on the memoir “Mad Love in New York City” written by Holmes. I was eager to read it after watching the movie, but it hasn’t been published yet. Josh explained why.

Josh Safdie: She has a few publishers who want to do it, but she’s like rethinking about how she wants to release it now that she’s done these two other movies and is now in the responsible world.

Ben Safdie: There’s a beautiful rawness to it. If you were to read the pages, it really feels like you were right there sitting next to her all the time and it’s beautiful. That kind of immediacy is also what really attracted me to it because first you hear about, oh, homeless person addicted to drugs. We’ve heard that story a million times. How do you tell that story in a new and different way? Her voice was that new way.

I came into this movie not knowing anything about its backstory, and I honestly thought Holmes was a highly trained actress as her performance is brilliant and mesmerizing. This, however, is not the case as she is not all that far removed from the addict we see on screen. She was a homeless addict for years but has managed to get herself cleaned up, and her performance in “Heaven Knows What” has earned her attention from many who want to make her a star. Both Josh and Ben described what it was like working with her.

JS: Her performance is incredible. You have to remember when you live on the street you’re performing on an everyday level. Whether you’re hustling this person or trying to get this thing out of that person, it’s a performance and a performative life. She was also moonlighting as a dominatrix where she literally was performing as a different character.

BS: One of the most difficult performances you can give is as yourself because you need to be able to understand what makes you tick and then be able to put that out there without any inhibition. And then that’s how you build other performances because if you can get at your core in its ugliest form, or whatever its form, you can build from there.

JS: Acting is just painting your personality a different color. I really was amazed. When I watch the movie now, as I get more and more distance from it just in terms of just having filmed it with a sense of making it, I watch Ari’s performance and I’m really in shock about it. It would take like six or seven takes to get the performative level because it would often start out with her enthusiasm level and how enthused she was to do the scene. Sometimes she was really in it and she would give us this incredible performance. Other times it would take 12 takes to get it out of her. It’s really a beautiful performance from her. And the guy, Caleb (Landry Jones, who plays Ilya), is an actor in Hollywood movies. That’s like the craziest performance because people don’t even realize that it’s a performance and they learn his real story that he is a Texan and that he was in “X-Men: First Class,” he was in “Contraband,” he was in “Antiviral,” he lives in Los Angeles. This is not him at all. Maybe there are traces of him in Ilia, but no, that’s not him.

What’s fascinating about “Heaven Knows What” is how it combines fiction with a raw cinema verite. It’s essentially a fictionalized version of true events, and yet it feels like we’re watching real life unfold right before our eyes. I asked the directors what it was like balancing out the fictional elements with the real-life ones while making this movie.

BS: I think it was about putting them in a blender and not knowing where that line was because that was the only way to make it successful. We made a documentary before this, and that was a documentary. That was a real person and we were trying to tell his real story, but in order to tell his story most effectively we had to use techniques from fiction filmmaking, reenactment and changing the timeline. We were fictionalizing reality there to get the point across. So here we are making a fiction film with a kind of documentary base, and again we had to employ the same kind of tools. You have to make things up to really get at the true emotional core of things. (Werner) Herzog says it’s like the ecstatic truth once you get there.

The movie also features a brilliant electronic score which serves to illustrate just how alien the world drug addicts inhabit is to the rest of us. Along with movies like “The Guest,” “It Follows” and “Ex Machina,” electronic film scores are making a big comeback. Josh and Ben talked about the movie’s composers and why they chose that kind of music.

JS: There’s a bunch of things that are happening in music in the movie. For the most part, we feature the work of Isao Tomita and his renditions of Debussy. We really wanted to have a romantic score, but this movie is like a time squared, nighttime vibe. It’s like electrified and it’s kind of seedy, and it’s an alien landscape almost. We like to say the movie takes place on Mars which is where an addict’s brain goes in a weird way. Debussy music is some of the most romantic music ever composed, but when it’s done through this Japanese mind from the 70’s it’s different. It’s reinterpreted. It’s no longer really romantic but it has its core in romanticism.

BS: There’s other music that we use throughout the movie. There’s some original music by Paul Grimstad in the hospital sequence, and then there’s Ariel Pink who’s a Los Angeles guy who wrote a song for the movie called “I Need a Minute.” It’s electrified as well, and he wanted it to be a love song to the locked bathroom, being able to lock your own bathroom and needing another minute while people are banging on the door.

Watching “Heaven Knows What” brings to mind movies like “Kids” and “Requiem for a Dream” which dealt with lifestyles which were unnerving and at times horrifying to witness. We want to look away and these films dare us to, but in the end we can’t avoid the reality of what people do to each other and themselves.

“Heaven Knows What” is now available to own and rent on DVD, Blu-ray and Digital.