In early 2017 the follow-up to Trainspotting will be released, over 20 years on from the original, with the characters all in "pretty different places" to where we left them.
Something that hasn't changed between the two films though is Irvine Welsh's view on how drug use is policed.
"It's not a war on drugs, it's a war on people," he told Dazed, a few decades on from penning the novel adapted by Danny Boyle. "The war on drugs is a war on you. It's a war on alternate lifestyles. It's a civil war - the state against the citizens."
Trainspotting, which revolved around a group of young, out-of-work heroin addicts in Edinburgh, wasn't about drugs, he said.
"It still resonates because it's not a book about drugs," the 59-year-old said. "These characters are all from the industrial working class, being made redundant, being made socially irrelevant in Britain. Twenty, thirty years later it's happening to the middle classes... we're rationing out the dregs of capitalism to people. That's why it resonates - people think 'we're in a dystopian future, what are we going to do?'. It's quite hard to come to terms with and often, the answer is drugs."
Boyle returns to direct T2, loosely based on Welsh's novel Porno, where we find Renton, Spud, Sick Boy and Begbie - played by the original cast - "all at pretty different places in their life". They've "responded to the last 20 years in different ways", said Welsh.
Whatever state we find the characters in, it will definitely be interesting.