Ruby Wax admits to Viv Hardwick that she didn’t set out with the intention of being the poster girl for mental illness, but arrives at Richmond tomorrow with a sell-out tour.

COMEDIAN turned campaigner Ruby Wax avoids using the term bipolar disorder to describe her own mental illness, preferring instead to use the term clinical depression before switching to just plain “mad”.

“I had it when it was young but we didn’t have a name for it, so I assumed it was some kind of a flu because I’d go to sleep. But it has nothing to do with being sad it’s a chemical malfunction that my mother had, but it isn’t necessarily inherited,”

explains Wax, who has sold out her one night appearance at the Georgian Theatre Royal tomorrow.

I ask her about taking the amazingly brave step of basing her show, Losing It, around her years of coping in a world which automatically shuns those who confess to mental illness.

“You have to do something very funny in order to say something that serious. So I’ve been trying to write serious comedy for ten years and I think this has hit the mark,” explains Wax.

She is going on to take a Master’s degree on mental dysfunction at Oxford University and wants her experiences to go into a West End run and a book rather than end up on TV.

“They’re filming the making of it but I don’t want the show to go on TV, I want to tour it around the world.

Once it’s on TV it’s out. I worked too long to see it all go out on TV,” explains Wax, who took a year to pull the script together using the songs of Judith Owen.

“She unbelievable and doesn’t speak, but sings under me so her songs are woven in and out. She becomes the feeling of what I talk about, because nobody has done this before,” says Wax.

Learning more about her own condition isn’t going to change the way Wax tackles performing which has seen her become one of the UK’s favourite Americans with 40 years of stage, stand-up, TV chat, celebrity interviewing, celebrity competing and wacky reporting.

“I wasn’t that talented but I invented something because I wasn’t an actress,” says Wax, who originally majored in psychology at the University of California.

“I’m not going to end up on stage lecturing. When I had my third child then somebody said I had clinical depression and I only had it once every five years, then you have to bring medication into it. A lot of the show is about the world we live in and it’s only towards the end that you realise that it affected me in this way. Everybody goes ‘oh yes, that’s me’, but they’re not necessarily mentally ill.

The show would be boring if it was all about mental illness. Everyone’s got a little proclivity, otherwise we wouldn’t have one-in-four sufferers and the number of suicides we do. It isn’t a rare disease.

“I talk about celebrity and envy and how excited we get when we see a star on TV. But there’s no manual on how to be a mother. Sometimes I’m with my kids and we squirt whipped cream on the cat and then we wait for our mother to come home… then I realise that I’m the mother. So who tells us this stuff,”

says Wax who feels that being busy is held up as a great status symbol.

“So if you’re not busy you have no meaning on Earth. But the busy-ness is what has driven me mad. Some can take it but most of us go under because we’ve got these role models that none of us can keep up with,”

she says.

But isn’t being labelled crazy often the end of a career?

“Yes, that’s completely true. I think to be honest it only came up because Comic Relief released a poster as part of a mental health campaign and, at first, I didn’t think it was going to be me. So it was on all the tube station walls and I couldn’t cover them all up, and I suddenly became the poster girl for mental illness.

Then I thought ‘if I’m hiding it everyone else is too’ and we’re doing these dates now where we’ve played in 20 mental institutions and it really works because we’re getting rid of the stigma,” says the mother-of-three who has undergone several periods of treatment at The Priory, the UK clinics which provides private mental health care.

During the second half of the show she discusses mental health issues with the audience and says “everybody starts talking because it’s so liberating”.

The unsympathetic will talk about “pulling yourself together” and often take the view that most disabilities, particularly mental, can be cured.

Wax, 59, responds: “Let’s talk about cancer in that case. It’s the same thing, except it’s not your cells dividing, it is a physical dysfunction.

I talk about it in the show. There is a dysfunction that happens whenever you have a mental illness and to say you must have a voice in your head to pull you out of it, is like saying that the Earth is flat. That’s insanity rather than someone having a mental disorder that you’re working at.”

■ Ruby Wax: Losing It, Georgian Theatre Royal, Richmond, tomorrow, Sold Out