Some people suspect psychopaths surround them, but writer Marty Faranan (Colin Farrell) knows it for a fact.

An Irish screenwriter who has run out of original ideas in a town where that’s career suicide, saddled with a girlfriend at the end of her rope (Abbie Cornish), Marty’s life is finally turned upside down by his well-meaning but insane best friend Billy (Sam Rockwell).

Before he knows what’s happened to him, Marty is an accomplice to his friend’s dog-knapping business until they make the biggest mistake of their lives -- pilfering the Shih Tzu belonging to mob boss Charlie Costello (Woody Harrelson), a man who would shoot your head off without a word but who still somehow adores his little puppy.

It’s the kind of shoot em’ up scenario that playwright McDonagh, 44, has made his stock in trade since his early Irish theatrical shockers like The Beauty Queen of Leenane set the theatrical world (and Broadway) on fire back in the late nineties.

Written and directed by McDonagh, Seven Psychopaths will probably be the general audience hit he has been hoping for when it opens this Friday. Previously McDonagh’s 2008’s independent flick In Bruges wowed the critics but really didn’t do the kind of box office business that the London-born Irish writer and director had hoped for.

But then Colin Farrell won a Golden Globe Award for his role and suddenly the film was back in play. Since then Dubliner Farrell has become a go-to actor forMcDonagh.

“We really like each other and share the same sense of humor and ideas about film and acting,” McDonagh tells the Irish Voice during an interview on Monday.

“It’s probably the sense of humor that’s completely on the same page and that’s why we do good work together.”

Since his debut at a theatrical wonder kid in the late nineties, McDonagh’s work has delighted in upsetting people’s expectations. He’s always been more punk rock than masterpiece theater, and he’d be the first to say so.

“The Clash and the Pogues and people like that were a big influence on me in my teens,” says McDonagh. “I guess as much as you want to be a part of the filmmaking or theater world, you kind of also want to question the parts you disagree with about them. I guess a punk rock sensibility frees you up to do that.”

Critics often say McDonagh “came from nowhere,” which is a kind of snooty code for saying he’s Irish and he’s working class. He’s hasn’t forgotten his roots at all.

“I guess when you come from my background it’s always going to be there. Success or being part of Hollywood or the theater community was never on the agenda. I just want to do good work,” he says.

“The success isn’t an issue really; it’s about expressing an opinion about the world that isn’t really being expressed maybe. That’s always there and I don’t think that’s going to change really.”

Now that his focus in Seven Psychopaths is on American gangsters McDonagh is free to explore one of the enduring elements of American drama -- guns.

“It’s something that in a playful way I kind of wanted to point out and question I guess. Why does every movie have to have guys with guns in it? I love those kinds of films, but I didn’t want to make one without poking fun a little bit or being a little satirical about it.”

The film leads to an explosive shootout at the Joshua Tree, that landmark made famous by U2 and that McDonagh loves for his own reasons. 

“I just always thought of it as a beautiful place. I went there for the first time about 10 years ago with the purpose of thinking about it being the location to end this film,” he says.

“I love those Sergio Leone spaghetti westerns and things like that, and it’s so close to Los Angeles too so it was a prefect place for the boys to end up.”

So Bono wasn’t a part of this equation? “No, not really. I swear. I was always more of a Pogues fan than a U2 fan.”

Read more: Colin Farrell sweats it out on the set of “Seven Psychopaths” - VIDEO

Fans of McDonagh’s Irish plays will want to know if he has plans to return to the landscape that brought him fame.

“I will yeah,” he says simply. “I’m always back in Connemara because my parents are back there and I’m back about three or four times a year myself. I mean John (his filmmaker brother) is just in the middle of his second one in Ireland and I hear all the stories that come from there,” McDonaghsays.

“I’ve got at least one play that I need to complete the Aran Islands trilogy so I’ll go back there with that story at some script.

What can fans expect? “I have a film script that I’ve had for a while that is based in Ireland too. I think it ends up in Connemara. So those places and things are always going to be present in my writing.”

This week Fox News brought up the number of homophobic statements made in Seven Psychopaths, and asked if it would generate a backlash from the gay community. Does he anticipate being placarded on opening night?

“Hopefully not. No one’s actually brought it up too much at screenings so far,” he says.

“I guess the heart or the hope of the piece is anti-racism and homophobia, as mine is. It’s interesting to play around with political correctness and I hope there isn’t any meanness to the film as a whole. But you know, if you’re writing crazy psychotic characters who are racist or whatever else then certain words are going to have to be used I think.”

But in the film the lads talk about women as complicating factors that just upset their day. There’s a real complicity between them that makes you wonder what’s going on?

“Oh really?” says McDonagh gamely.

I tell him they sound like they’d rather spend time witch each other until they get self-conscious about it and compensate by talking about gays.

“I guess I can be accused of going down that road in the past. I don’t know it’s more just playing up the fun of that,” he says.

“It was a fun just playing up the exploration of the character more than anything. I’m not saying it’s how men ought to be.”

Meanwhile, he admits how important Ireland was to his creative life.

“I thinking going back and forth to Ireland so much as a kid had a major influence on me. And going to Connemara rather than Dublin had a definite impact on my storytelling and all of that.”

And how is directing Colin Farrell? “I honestly don’t give him much direction,” McDonagh confesses. “He just loves the characters and it’s more about getting out of the way of a great script. People forget sometimes how great of an actor he is.”

Mickey Rourkewas originally slated to play the villain until he bowed out and the role went to Woody Harrelson instead. What happened there? “This was a pretty low budget film and his people wanted more than we were able to afford. There wasn’t too much anger on my side for sure. It just didn’t work out.  He’s a fantastic actor,” McDonagh says.

The final questions are the ones I have most wanted to ask him. McDonagh’s plays are full of torture, murder and mayhem. Their violence factors set new records on Broadway. Has he enjoyed pushing the boundaries? Has it been a laugh for him? “Completely. I mean to get to stage some of the most outrageous possible things and then to find the morality and sweetness at its heart is kind of joyful. To have gotten away with it for long!”

Here's the trailer for Martin McDonagh's "Seven Psychopaths":