From "The Sixth Sense" to "Old", director M. Night Shyamalan has had a unique string of hits, but these days he works outside the Hollywood studio system, which he says has grown "sick".

Balancing art and commerce has always been the great game of Hollywood and few have played it as well as Shyamalan, who returns to cinemas next week with the apocalyptic horror tale, "Knock at the Cabin".

Still just 52, he has been cranking out box office hits every couple of years since the iconic "The Sixth Sense" in 1999, through "Unbreakable", "Signs", "Split" and many more.

They have been almost entirely original, rarely based on pre-existing franchises or superhero characters that the major studios now rely upon.

Watching how Hollywood has evolved in that time has left him deeply disillusioned.

"If you look at the industry right now... there are movies that feel incestuous, they're just masturbatory... It's just Hollywood talking to themselves," he told AFP.

"And then there are movies where they're saying: the audience is dumb so we're going to take all the soul out and we're just going to do it by numbers," he said.

"These are signs of complete dysfunction."

He looks back in wonder at his breakthrough year in 1999, when studios backed several highly original films such as "American Beauty", "Magnolia", "Being John Malkovich" and "The Insider".

"The industry was different then. It was aimed at -- how do you get the best storytellers to tell stories for the widest audience? That's not the case now," Shyamalan said.

- 'Huge risks' -

His response has been to go it alone, even if that means giving up on big budgets.

"I found the only way is to leave the system and pay for it myself... to make small movies but take huge risks -- not having to ask whether they like having a gay couple at the centre, or whether I should hire a wrestler..." he said.

"This is my way of staying healthy after spending a long time in a kind of sick industry," he added.

"Knock at the Cabin" stars former wrestler Dave Bautista in the story of a family isolated in the woods who are taken hostage by an armed group and told they must sacrifice one of their own to avert the apocalypse.

At the core, said Shyamalan, is a question that resonates in our "post-truth era": do we trust each other?

"Does the husband believe in the other husband? Do they believe what the strangers are saying? Do we believe in our society and what we're seeing?"

And of course, being a Shyamalan film, there are plenty of twists, which he still loves to write.

"That's the fun part!" he said. "Even until late in the writing of the movie I was like, how many times can I flip you back and forth? Because I had thought of another way, and I was worried the audience are going to get whiplash if I do one more," he said.