Earlier this year, black comedy film The Voices – starring Ryan Reynolds – became one of the surprise packages of 2015. Combining uncomfortable laughs with real horror and stunning surrealism, it was an interesting piece of work that proved a bizarre treat in amongst this year’s dollop of blockbuster fare.

The Voices arrives on Blu-ray in the UK on Monday and, ahead of its release, I got the chance to talk to writer Michael R Perry about everything from Ryan Reynolds to cats, dogs and disembodied heads.

What inspired you to come up with the original idea that would become The Voices?

It gestated in the back of my mind for a while. It all started in Wisconsin. My brother-in-law worked in a big, old plumbing manufacturer at the same time as my sister worked for a foundation that preserved art created by people who saw the world in different ways, many of whom had various levels of mental illness.

At the same time, I was reading a lot of books about guys like Ed Gein, Edmund Kemper and so on; and the three threads converged: a radically different way of seeing the world, motiveless murders, and a plumbing factory.

Some time later, when I sat down to write it, I realized that this man’s voices would seem to come from outside for him, which became Bosco and Mr Whiskers. Mr Whiskers’ attitude was based on the outraged voice of a guy I knew, who was extremely bright and colourful, but harshly negative.

How would you describe the film’s genre?

It defies easy categorization. It was always a drama with comic elements. The humour is always a way to express Jerry’s inner life, but it’s not a comedy in the same way as something like The Hangover. The people who made the American ads hit the comedy angle pretty hard and so some viewers were confused when seeing the movie, which is quite emotional and gets real about Jerry’s suffering.

The Voices feels like an enormous risk of a film that pays off. Tell me about the journey to get it made.

I wrote the entire script before anyone read it. My agent sent it to [producer] Roy Lee, who really liked it, and told me that it wouldn’t be easy, but he was going to put in the work to figure out how to get it made.

Roy struggled for two years to get all the puzzle pieces in place and then got it to Mandalay Vision and producer Matthew Rhodes. Marjane Satrapi read the script and came to the producers, saying "I want to make this movie".

She then persuaded our amazing cast to come aboard, as well as our outrageously great crew. It takes about 25 things in a row to go right for a movie to get made, and they all did for The Voices.

How did you go about balancing the film’s horror aspects with its comedic aspects?

The balance all had to do with character. I really thought, non-stop, about trying to paint a picture of the world as Jerry sees it. When he’s shocked, we’re shocked; when he’s happy, we’re happy; when he’s sad, we’re sad. The horror elements are natural to the story.

Ryan Reynolds is winning plaudits for his lead performance. Did you have anyone in mind when you wrote the role and how do you think Ryan did?

Ryan Reynolds was astonishingly great. I didn’t write it with anyone in particular in mind, but once Ryan was cast, I could not think of any other actor in the role.

He’s brilliant and brought the whole range of skills to his interpretation, knowing when to be funny, when to be earnest and how far to push any particular detail.

What about the rest of the cast?

I didn’t write the roles for anyone in particular, but after Marjane Satrapi cast both Anna Kendrick and Gemma Arterton I could think of no one else playing those parts.

Arterton deeply understood that she was playing two completely different characters, one of which was a real person, the second of which was a figment of Jerry’s fractured psyche. If you watch the film a second time, you’ll see that Fiona-alive and Fiona-in-the-fridge are utterly separate performances. She captured the humour and the pathos, both as a real person and as a portion of Jerry’s vision.

Anna Kendrick is a delight to watch. She’s one of those performers who seems to admit you to her private emotions. There was more dialogue for her, explaining who she is and where she came from, on the night that Jerry and she get to know each other, but Marjane Satrapi’s instinct was “less is more”. When you have an actress of Kendrick’s calibre, it’s stronger to let her visual performance carry the story. Satrapi’s instinct was spot-on. Kendrick is amazing.

You use a dog and a cat to personify good and evil. What made you decide to do that?

I had a relative who died shortly before I wrote The Voices, who in many ways saw the world as Mr Whiskers does. Mr Whiskers isn’t evil, exactly, he’s a “truth teller” who never hesitates to articulate the worst-case scenario, in hilarious, graphic and picturesque language.

When you grow up around someone whose speech and attitudes are so forceful and hilarious, they keep talking to you even after they’re gone. Putting my late relative’s words into a cat’s mouth was a perfect fit, but then I added the things a cat really might think and do as an extra layer.

Bosco is that dog, or friend, who almost always makes you feel good about yourself, no matter what you’ve done. It’s called “Unconditional Positive Regard” in psychology. When he finally turns on Jerry, it’s pretty hard-hitting because it means Jerry’s really crossed the line.

The film has a really interesting visual style, including use of bright, pastel colours. Was that something you talked about in the script or was it solely the vision of the director?

The script specifies that the world as Jerry sees it is utterly different than the world as it actually is, without filling in every detail. In the screenplay, I articulate the narrative and emotional feel of the two worlds; the specific implementation was entirely Marjane Satrapi’s brilliance.

We had long discussions about what the two worlds are like but I never second-guessed Satrapi’s choices. I only helped her implement them. I felt that no one was looking over my shoulder as I wrote the screenplay, and an artist like Satrapi deserves that same freedom.

My contribution was: “a bright and idealized world, not quite right but not so different that you notice right away”. The masterful visual control, the pink forklifts, the happy rain of packing popcorn is pure Marjane Satrapi.

How would you sell The Voices, in one line, to someone who knew nothing about it?

“A man who is bringing his life back together after a psychological crisis is succeeding on every front — at work, he’s well-liked; he has a crush on a girl; his shrink is impressed — and everything is going swimmingly until his cat starts telling him to kill people.”

It’s a long line!

What’s next for you and your career?

Look for work! I’m always writing something new.

I consulted on new AMC series Into the Badlands, helping to work out the six episodes of that series, which Gough & Millar created. It’s an amazing post-apocalyptic martial arts show.

NOTE: The questions below the next big image will contain spoilers. Do not read below this image if you haven’t seen The Voices.

Do you think Jerry is a sympathetic character, overall, given the remorse he shows towards the end of The Voices?

That’s a great question. Jerry, as seen from the outside world, would be vilified in the press and courtroom, if he were ever caught, as one of the worst people in the world. The challenge of the movie was to try to find empathy for this man, to see the world through his eyes and to understand, but never excuse or justify, his actions. I think he’s a sympathetic character who has done some extraordinarily bad things.

Jerry’s death feels logical in the context of The Voices. Was that always the plan?

That was the plan from the very first draft of the script. I imagined that, in his dying moments, Jerry would revisit the happiest time of his life, which was the day of the company picnic. His oxygen-deprived mind reconstructs his life as he might have wanted to live it. Even as he’s dying, we stay within his subjective point-of-view.

The Voices ends with an off-kilter musical number. What inspired this decision?

The dance with Fiona was the first moment Jerry felt accepted into the greater world. It was a beautiful breakthrough for him and he associated it with the music and festive occasion of an office party. Most other people would have grudgingly suffered through having to go to work on a Saturday and see the same people yet again, but for Jerry it was the high point of his life. It made sense that he’d go back there in his mind as he was dying.

In the script, they did the ‘Macarena’ at the picnic, instead of a conga line, but Marjane said she would lose her mind if she had to hear that song over and over for six months. I think the O’Jays track ‘Sing A Happy Song’ is a perfect fit.

Thank you very much, Michael R Perry! The Voices is available on Blu-ray from Monday, courtesy of Arrow Films.