Maya Forbes’ new feature Infinitely Polar Bear is unlike anything she’s ever written for the screen before, and that’s a very good thing. That’s not a knock on the great work she’s done in a long, successful career that spans The Larry Sanders Show and features like Monsters vs. Aliens and The Rocker, it’s that Polar Bear is her long-delayed personal story – one that’s as hard to fit in a logline as it is worth telling.

Forbes makes her directorial debut with her script telling a slightly modified version of her childhood growing up in Massachusetts as the daughter of a black mother and a white, Boston blue-blood father who also happened to be manic-depressive. Because her father had no access to the family fortune, the family lived near poverty and her mother was forced to make the heart-wrenching decision to earn an MBA in New York, leaving the kids in the charge of their colorful, loving, but far less than stable father.

The complicated tale is not told verbatim, but after literally years of trying to “Hollywood” the script, Forbes discovered telling the truth was the most powerful narrative tack. Mark Ruffalo brings innate charm to the father, Cam, and Zoe Saldana a dose of threadbare glamour to the mother, giving the film the forthright magic of a true story that comfortably understands it’s also entertainment.

This balance is struck here between brave truth and skilled moviemaking thanks to Forbes’ veteran hand at pacing, structure and dialogue, molding material that, in other hands, would prove too quirky. Even the film’s title reflects that challenge; Forbes’ little sister – played by Ashley Aufderheide, while Forbes younger self is portrayed with documentary authenticity by her own daughter Imogene Wolodarsky – referred to her father’s condition as “polar bear.” While they were in college the sisters had to admit their father, who had a particular love for locution, to the hospital as he was careening into a manic episode. When asked to enter a previous diagnosis on an entry form he wrote, in a touching homage to his youngest daughter’s malaprop: “infinitely polar bear.” Since the film needed to compress time to avoid recasting the kids, this title event didn’t make it into the film.

Forbes spoke with the Writers Guild of America West website about the decades-long writing of the script, the effect casting played on it, and how, at long last, the truth really set it free.

Exactly how autobiographical is this script, and how much did you modify it for the sake of the movie?

Of course you have to modify it a lot. For instance, it happened over the course of many, many years, which would have involved recasting these kids. So you have to kind of compress things. I wanted to tell a story of how my sister and I ended up being taken care of by our dad. Because I had written Hollywood studio films for a long time, I started trying to figure out how to make it relatable to people. Should the parents be divorced? Is the mother dead? Would anyone understand why this mother leaves the kids with the dad? That’s a big challenge, how do you explain these things?

So you’re trying to take this incredibly singular story, but still applying your skill for Hollywood script making to the story?

Yes. That’s where I started. I was also thinking, How do I make this father likeable? How am I going to make this guy likeable?

Mark Ruffalo!

Haha. But how do you get Mark Ruffalo to do it? That’s the question. I was grappling with these typical questions that you get bombarded with when you’re writing a studio movie, and I just felt like I was coming up with something that was really not distinct and bland. So I sort of jettisoned all of those concerns and just tried to go at the truth, which was, back to your first question, that my father was a manic-depressive. He was from a wealthy family, but we had no money. My mother was black. She was really struggling to get a good job. She went to business school, and she left us with our father. I stopped worrying about making the father likeable. I thought, I’m not going to try to make him likeable…

To that specific point, we did a movie recently, Welcome To Me, which starred Kristin Wiig as a bipolar character, I don’t know if you’ve seen it….

I haven’t seen it but I know what it is.

It’s not anything like your film at all…but from a writing standpoint capturing a character with that condition is difficult – depicting the selfish, even damaging reality of manic depression while still making the character empathetic for the audience. How did you grapple with that?

Once I stopped trying to make him likeable, I just wrote him as he was, which was a complicated person with all kinds of shades – a theatrical person and a funny person. The dynamic that we had was funny. This was the critical break for me: I have two little girls and my husband went away to India for six weeks when the kids were eight and six. He was making a movie there. So he was gone, and I was taking care of the girls. My kids are pretty well behaved. My sister and I were not well behaved. We were opinionated little brats who were fierce and never tried to make anything easy for anybody. I have girls that get along pretty well with me and each other, but it was so hard taking care of them, that I thought, Holy shit, I cannot believe my father did this! How did he do this? It was the moment where I realized I have empathy for him – I mean, I always have had empathy, but I can’t believe he did it! We just put him through the ringer. We never were nice.

The empathy for him having to care for you solo…

Yes. It gave me perspective on the script… I probably started out writing [it] from a harsher and angrier place and in the course of writing it I came to have empathy for all the characters. I, of course, had empathy for these two little girls who are stuck in this crummy situation, and I had empathy for my father dealing with these two kids, and I had such empathy for my mother.

As I was working on it, I was sort of digging around in the past and the specific cultural peculiarities of the world my father came from. He was from a wealthy family, and they had all gone to Harvard, and they all had gotten everything and a lot of them hadn’t really done anything. They got to a point where [they thought], Education, meh, big deal. My mother, being black, understood that education is everything. She thought fiercely [that] you will never sustain where you are or keep moving up without education. My dad’s family, who I also loved, were like landed gentry or something. Everything is just supposed to come easily to you, and you’re not supposed to strive – that was a bad word for us, striving. I grew up with the idea that you’re not supposed to strive, that it was unappealing. At a certain point I thought, I want to strive, that’s what it’s all about, striving! But it was having empathy for him taking care of us. And there was a lot of comedy there – he’s this man and these two kids are just giving him such a hard time. It’s kind of like The Bad News Bears, Tatum O’Neal facing off against Walter Matthau…

And to that point, how much did you lighten the reality here?

It’s an interesting thing. There was a scene early on that was really pretty heavy, during the manic period. It’s a lot to hit people with right off the bat in a movie, and then to have the mom say, “Okay, I’m leaving.” I had to think about what's the real truth? There were bad moments. He was a great father in many ways, and that’s the core of why she could go, you know? So, yes life can get pretty dicey. But if you’re a great father 90 percent of the time, and then you’re scary 10 percent of the time, how do you balance that?

That’s what I’m asking. I understand the overwhelming conclusion was that he was a good dad, and a great influential character. But from the writing standpoint, how much did you lighten or navigate away from you know, unpleasantness?

In writing I didn’t as much. In editing I did. It was different when you actually sat down and watched the movie.

So you shot some darker stuff?

Yeah. In the first 15 minutes of the movie – when you’re cutting any movie you’re like, get to the story, get to the story. So there was that. But it was also, how much can I lay in to the scary part? Manic breakdowns are scary. But you know what’s funny? When I wrote I probably upped the scariness from real life.

In the beginning [of the film] when they’re in the country, his manic turn to anger, I juiced that up. I kind of emphasized it in the writing, and when I watched it, I was like, Maybe that’s too much. But yeah, my father had some pretty big deal manic episodes, but usually not around us. There were things that happened, but they weren’t things I witnessed as much. I’ve certainly seen the manic many times in my life, but not violent. But he could get violent, as he does in the movie, and it was uncontrollable, but it wasn’t around us.

You are a veteran writer and this is the first thing you’ve done of a personal nature, the story often turns on these unique, true details – like your dad making really good crepes. Has that changed you as a writer?

I think so. No matter what I’m doing, a studio movie or anything, I’ve always tried to connect emotionally with it. But there’s more of a trust in my own experience, you know, recognition that the specific is universal, as opposed to trying to go for the universal, which is often what happens when you’re writing and there are a million cooks in the kitchen and everybody has an opinion. Here, you kind of have to say, “This is how I felt, this I what I thought. So I know that this has a ring of truth to it.”

Trusting in the complicated truth?

Yes. Trusting that things can be more complicated, they don’t have to be spoon fed to people. People will connect to things that have specificity.

What is your writing routine? Do you have a system down? In terms of where you write, the time of day, what you do it on – that kind of stuff?

I try to – I have so many friends that get up at five a.m. and write. I’m not that person. I have three kids, I have a little boy whose six. I get up and I try to be sitting down to write by 9:30 or 10. I have a chair in my bedroom that is a sort of comfortable loungey type chair. I write on my laptop, and I will just sit there for hours.

In the bedroom, wow.

I know. I had an office. But I got a chair in my bedroom, and now…

You just love it?

I just love it.

That’s really – I’ve never heard that one.

Really?

No, not a bedroom and a loungey chair. That goes against all kinds of conventional wisdom. But it’s amazing.

And often, if I’m writing with my husband, because he has an office down the hall, he drags his chair in there, and we’ll sit together. But if I’m on my own – and we kind of do both – I’ll often just plug in some headphones and listen to the same song over and over on a loop…

Because it gets to the point…?

It’s like white noise. It’s a mood, but I’m not really paying attention to it, and I’ll play 100 times before I even look at what’s around.

Obviously, there are some great songs in the film. Are there any tracks that are really representative of the time that you were writing this?

Let’s see. I was listening to Ike and Tina Turner a lot. That George Harrison song, Run of the Mill, was playing a lot when I was in the middle of writing the script – I was always in the middle – but I was closing in what the final script would be, I had that perspective shift and I understood that part of the comedy and the fun of it was that this guy, as difficult as he is, got these difficult kids. Someone played that George Harrison song in the other room, and I heard it and said, “That! What is that?” It’s just incredible. It’s sort of mournful.

As you were writing, you knew you wanted to direct this. At what stage did you have an actor in mind?

I didn’t. When I let go of making the character likable and just trying to capture the person, I didn’t think about anybody really. I just tried to think about the real people.

Did you have to do a little readjusting when you finally got the script to shooting and having Ruffalo play the part? ‘Cuz a person just innately brings themselves, their thing.

Yes. And that was really important to me. So it was important when I met Ruffalo, I felt like he got this on a deep level. And there was a lot of my father in him. They shared many things. Now, my father was not an incredibly brilliant and successful actor, so that was useful.

But what’s interesting about the semi-autobiographical part of it is that you write this thing, you write it, and it’s really personal. But the actors, and also the limitations in terms of location – like we spent our life in Harvard Square – that doesn’t exist anymore and I’m not going to recreate it for the film – so there are a lot of changes that have to be made just making it work as a movie. But the actors, Zoe and Mark, they bring their own thing. With Mark, I really worked with him on the world my father came from, but when we ultimately got to set, I wanted him to bring himself, to be himself – with these other touches. I said, “I want you to really savor words, and I want you to speak with a crisp diction, and to hold yourself in this way. But then I don’t want you to put on airs, that’s not who you are, that’s not who this character is.”

It’s so inherent in the character that he’s authentic, himself.

Yes exactly. So we did all the preparation, because he was attached for a few years as we tried to get the money. And so it was sort of welling up – he was getting in touch with who this person was over these years. It was important to me that he kind of let a lot of that go and bring himself, [so it felt] really authentic, especially when you’re playing bipolar, that’s just who you are. It’s not this thing that happens to you. I have many bipolar people in my life, and I’m always struck by how there’s moments where I’m saying, “Are you manic right now, or are you just yourself?” It’s just dialed up. It’s hard to know.