In the novel, Mark Renton and his mates choose drugs, prescription pills bought on the black market and heroin. They are part of what Welsh has labelled "the chemical generation". Mark's parents, like the other middle-aged people in the book, are horrified by the drug-taking, the wasted opportunities, but as Welsh underlines beautifully, they resort to the "acceptable" drugs of their own generation - booze, fags and Valium.
Some parents, and some educators, have been nervous about the subject matter and Welsh's treatment of it. After years of anti-drug campaigning, of slogans like "just say no", here are texts which explain in graphic detail why young people want to take drugs, how they take drugs, and what it does to them.
It seems to me that the book is a grim and honest portrayal of the chemical generation, full of black humour, irony and an underlying vibrancy, which ultimately offers a profoundly anti-drug message, without shirking from showing what attracts Mark to drug culture. That makes some people nervous - Aesop's fables it's not.
Some people have reacted angrily, saying Welsh's books are unsuitable reading. The notion of the modern writer as guardian of society's morals, is interesting, but crazy. Like many before him, Welsh is exploring.
It used to be fashionable in the 18th century to make an avowal in the preface of moral precepts to be learned from a text, but often these simply licensed readers to enjoy a prurient read. Much as the tabloids do now, I suppose. Welsh's novel is neither "right" or "wrong" in the way it treats the drug issue, it is a creative text, not an anti-drugs leaflet.
Many of my students have chosen the book, play or the film as a text to review for assessment. Most have been drawn to study the text in its three forms. They have commented on how both the play and the film have turned up the humour, increased the "laddishness" of Renton and his pals, and taken some of the teeth from the novel. But they take a strong anti-drug message from all three.
Despite the explosion of public reaction Welsh is actually doing some very old-fashioned things. He is allowing his readers to learn through vicarious experience. Yes, readers are treated to an intimate portrayal of drug-taking, but it doesn't follow they are eager to emulate Renton co. They do, however, have a chance to enter into a text which will teach them something about life. And faced with a complex world, young people have never been so desperate for information which will enable them to make an informed choice.
Welsh's book has shown up a generation gap. Many drug counsellors have admitted that the new designer-drug cult has highlighted their ignorance. Designer drugs, placed within a youth culture of music and dance, are no longer on the margins of society. Traditional anti-drug approaches are seen to be failing.
We need to find a way to educate so young people will listen. It has been shown that the "just say no" campaign is not effective enough. What young people want is accurate, honest information. National studies have revealed appalling ignorance among young people about the long-term effects of drugs.
In further education we have a particularly vulnerable client group: young adults, many of whom have just cut the apron strings to embark on an independent lifestyle where they are subject to new pressures. If society has a drug problem it would be folly to assume that our students are safe.
In September last year our college began a drugs peer education project. The project planned to provide practical, honest and accurate information about drugs and the effects of using them.
Students were recruited after workshop sessions and seven underwent training. They are presently negotiating time slots with course leaders so that they can run structured workshops with classes. The workshops are planned to be fun, and involve a great deal of student participation - a floor game, created by the group themselves, allows participants to focus on recreational and experimental drug information.
In Trainspotting, Mark Renton talks about choice. He sees a distorted dichotomy: the heightened existence of life on drugs or a boring conformity. What the text reveals is the reality of addiction.
Many will still be nervous of Welsh and his subject matter. Many will be fear the switch from "just say no" to the concept of informed choice. Many will confuse the provision of accurate information with encouragement. Yes, education is dangerous. But not as dangerous as ignorance.
Carol Gow is a lecturer in media and communications at Dundee College