Heroin, AIDs and violence are enough to make most stop in their tracks. They did in 1993 when Scottish author Irvine Welsh released his critically acclaimed debut novel “Trainspotting,” which followed the lives of heroin addicts in Edinburgh, Scotland. Its 1996 film adaptation starring Ewan McGregor was a global success. Welsh’s projects since “Trainspotting,” include the 2002 sequel “Porno” and nine other novels. Now he has revisited his well-known characters with a prequel about the gang’s pre-heroin days called “Skagboys,” which was released in the U.S.

Sept. 17.

Welsh now lives in Chicago and spent some time with The Chronicle to talk about his new book, the tough issues his series tackles and what’s on his horizon.

The Chronicle: You wrote “Trainspotting” quite a while ago. What made you bring back the characters?

Irvine Welsh: I had 100,000 words I didn’t use at the start of “Trainspotting” and another 100,000 at the end because I didn’t really know anything about writing books back then. So I just chopped the middle and wrote “Trainspotting.” I realized that the material was there to write a book not about them being junkies, but how they became junkies and what happened to their community, and their society and family relationships.

I think they’re very iconic characters in a lot of ways. In some ways, they were archetypes. People all over the world say, “We’ve got a Sick Boy. We’ve got a Begbie.” They identify with the cynical intellectual, the compulsive womanizer, the loser with a guitar and the psychopath. Everybody’s kind of hard. Maybe not as extreme as that, but they’ve had some kind of friend who fits that kind of bill in some way or the other.

Why did you choose to set these books in Edinburgh?

The whole thing about “Skagboys” was when Edinburgh became the AIDS capital of Europe; it was an investigation into that. It is a look at what happened to Edinburgh right from the Scottish Enlightenment, the Industrial Revolution, the growth of medicine and what happened there which led to the setting up of a heroin plant, which kind of led to the abuse of heroin locally, which led to AIDS through the sharing of industrial-size needles and syringes. So there’s kind of an inevitability of it happening there, in terms of the city’s history.

You tackled a lot of tough issues that were relevant to the city at the time. Do you think you do the same in “Skagboys”?

I think “Skagboys” more so. “Trainspotting” is more about the characters in their own subcultures looking out in the world. “Skagboys” is more about looking in on their world, basically, and all the things that have shaped the world they live in.

Do you think “Skagboys” might translate to a movie?

I think it’s probably more suited to be a TV series. We’re investigating that possibility. I think that will be my next big project to get into next year.

“Skagboys” debuted at No. 1 in Great Britain in April. Did you expect that?

No, not at all, because all these big airport novelists—James Patterson, John Grisham, Jeffrey Archer—all had books released on the same day. I was thinking if it got [in the] Top 10 or even Top 5, that would be good. But to go straight to No. 1 was a very big surprise but a pleasant one.

How do you think your writing and voice have changed since your first novel?

As a writer, you’re always messing around with different voices. The novel I’m doing right now is narrated by two American women. One’s an artist, and one’s a fitness instructor. I think you also have your own voice as an author, but if you’re writing a lot of stuff in first person, which I like to do, you have to find the voice of a different character.

What else can we expect from you in the future?

I’m working with HBO on a TV series and trying to get that into position. I’m working on another TV pilot, a show with Iggy Pop, Jonas Akerlund and Arthur Baker, which is going to be set in Miami. I’m looking at doing a film in Chicago in the summer. I’m working on a couple of big theater projects in London, so quite a lot going on.

For more information on Welsh, visit IrvineWelsh.net.