"It's funny 'cause it's true," Cook says. "People in the arts often struggle with their mental health."

The uncertainty arising from the sporadic nature of work and the frequent rejection are certainly not conducive to a mentally health life. And that's certainly the case for the character here.

"The play is about a guy called Dave who finds himself in the midst of a crisis that's been coming up on him his whole life he hasn't been aware of," Cook says. "He's haunted by his past ... He's using substances to numb himself."

Dave is 35, seven years younger than his creator ("I look 35, young for my age") and has been through addiction, rehab and recovery.

Now things are getting bad again. But eventually he is thrown an unlikely lifeline and winds up in Thailand.

Breaking the Castle is Cook's first adult play. Some of it is drawn from his own experiences, and those of other people he's met.

"I lived in Kings Cross - I was susceptible to this kind of stuff," he says. "But it's not an autobiographical show in the sense that this is my life story."

Cook says the process of exploration in writing the play enabled him to look back at his life and reflect on it and how he came to be where he is.

While Breaking the Castle might sound heavy, and sometimes is, he says there's a lot of humour throughout it. And, ultimately, he says it is "uplifting. It celebrates our ability as human beings to persevere. There's a spiritual element to it."

Dave, he says, is looking for purpose and meaning in his life as well as the help to make things better. The title refers to breaking through the "castle" he's built around himself in his life.

Cook thinks mental health issues are still not taken seriously enough in Australia and the play is, in part, a way to confront this.

Breaking the Castle is directed by the Street's artistic director, Caroline Stacey and was developed there.

"In 2019 I applied to The Street Theatre's First Seen program based on 10 pages of script I had under development."

He spent the rest of the year working on the script. "I've lost count of how many drafts I've written. It's been - not rushed, but an intense period to get it up."

Cook, who was born in Brisbane, says he spent most of his teenage years wanting to play rugby union for Australia. He had been in plays at high school and although he studied journalism he decided to audition for the Victorian College of the Arts and was accepted.

"I had no idea what to expect from acting," he says.

The course was tough. There were culls every year, and of 28 who started the same year as him, only 12 graduated - but Cook was one of them. Since then he has amassed a substantial number of stage, TV and film credits. He's worked for Queensland Theatre Company, Bell Shakespeare among others.

He was the head of acting at the Aboriginal Centre for Performing Arts in Brisbane where he also devised new works with the students. He has worked as an arts educator and has written, devised and directed numerous plays with students across Australia.

This is his fourth show at the Street Theatre; most recently, he was in The Chain Bridge, also directed by Stacey.

Cook says he would like to keep acting and writing, and ideally write plays in which he could act, "but not so much one-man shows. As a writer, it's your voice - you get to say what you want to say as an artist."

Breaking The Castle. By Peter Cook. Directed by Caroline Stacey. The Street Theatre. February 29-March 12. thestreet.org.au.