Writer and director Anthony Neilson is pleased that the National Theatre of Scotland is touring his show, The Wonderful World Of Dissocia, as he'd like to convince the world that the land of his birth "isn't all haggis and shortcake".

He's an Artistic Associate of the NTS which, since its first performance in February 2006, has created 28 productions in 62 different locations, including theatres, ferries, forests, airports and village halls.

"I'm in touch with them regularly and put my oar in every now and then. It's something I feel very optimistic about. There are very promising things ahead," he says.

"I'm pleased we're not going down this very parochial route and just doing another show about crofts, that's terrible minority theatre. Although there are communities out there that can be served."

The Wonderful World Of Dissocia is a piece about which he's said, "If you like Alice in Wonderland, but there's not enough sex and violence in it, then Dissocia is the show for you".

The NTS didn't exist when Dissocia premiered in Edinburgh and became a big hit, picking up five prizes at the Critics Awards for Theatre in Scotland. Part of NTS's remit is to bring back to attention work it feels needs to be seen, so the show's been remounted for London and a tour.

This "creator of pioneering, taboo-breaking work" is noted for writing and directing "witty, bold and compassionate plays that explore uncharted psychological territories". Clearly, he's not going to be to every audience member's taste but has noticed a shift in people's reaction to the production.

"When we first did it at the festival it was strangely unanimous, everyone seemed to love it. People who hate it don't tend to come up to tell me. This time it has been very contentious. In London, it divided people more. I'm used to that," he says.

"Formally, it's quite an odd play. Very understandable and accessible, but the first half is very robust and has songs and a certain type of humour.

"The first half has one foot in the variety hall which is maybe a Scottish thing. There's a lot of punning in it and that's unacceptable to a certain section of London audience. They like their humour very dry - and it ain't that."

The play follows Lisa Jones on a journey into a world, Dissocia, whose inhabitants are a curious blend of the funny, the friendly and the brutal.

"Ostensibly, the show deals with mental illness, which always seems a bit grim, but I wanted to do in as ungrim a way as possible," says Neilsen.

"The starting point was simple - why some people, who have psychiatric conditions, find it very difficult to take medication. Why there's a resistance to that, why there's a part that wants to keep that condition going when everyone around them can see it's going to ruin them."

His working methods see him start with the actors and a basic idea, although, unusually, he'd done some preliminary research with students on Dissocia.

"It's not exactly Mike Leigh's style because I don't have the actors improvise and then produce a script. What I do is more authorial than that. There's more of a writer's voice.

"I pretty much make up the material, but it's really a way of creating a personal feeling of an audience within the rehearsal room. I bring in, say, five pages and watch them read for the first time, and react as an audience would and try to experience it the way they would."

He's not complaining if people don't like Dissocia. Having them discuss the piece is a welcome by-product of the production for him. "It's good, it's healthy," is his attitude.

He's putting forward a particular argument in the production. "It's really an experiential thing, getting people to feel what someone in that position may feel from the inside. It's their point of view rather than my making any statement," he explains.

Audience reaction varies from venue to venue, he finds. "Generally, audiences seem to be liking it. It was all sold out in London. When you go out on tour, audience attendances vary."

Neilsen isn't the sort of director you expect to find directing more traditional plays, although says he has no objection to do that. "If you've been writing and directing for a while, people assume that's your thing," he says. "I don't have any problem with that kind of old school type of theatre."

He confesses that, away from work, you're more likely to find him in the cinema than the theatre. "I don't go to the theatre that much. I go but mainly to things I feel obliged to see because friends are in them. It's difficult for me to go and watch a play with the right attitude, I tend to go to the cinema a bit more.," he says.

Both his parents were in the theatre - his father mainly as a director, his mother as an actress - and he's always believed it's a very exciting form. "I still believe in it and believe that a good show in the theatre is a great experience," he says.

"It saddens me a little, it's falling out of the ring of public leisure options for many people. But then a bad night in the theatre can be absolutely awful.

"My aim was to make work that was accessible and took advantage of the fact it was live. It was not like I started out as a plumber and then thought I'll go and have a life in the theatre. I always wanted to go down that road and found it happening."

Theatre in Scotland in the 1970s was very vibrant, something that obviously rubbed off on him. "There was a burst of creativity, very political, very committed pieces. A lot of it quite tough, very populist as well. That was all an influence."

The Wonderful World Of Dissocia: York Theatre Royal from May 22-26 (tickets 01904-623568) and Northern Stage, Newcastle, from June 12-16 (tickets 0191-2305151).