Irvine Welsh with the same name in 2013. "Glue" (2001) was a return to the locations, themes and episodic form of "Trainspotting", telling the stories of four characters spanning several decades in their lives and the bonds that held them together. Having revisited some of them in passing in "Glue", Welsh brought most of the "Trainspotting" characters back for a sequel, "Porno", in 2002. In this book Welsh explores the impact of pornography on the individuals involved in producing it, as well as society as a whole, and the impact of ageing and maturity in individuals against their will. The book is
Heroin users, compared to morphine, reportedly stems from its perceived different effects. Short-term addiction studies by the same researchers demonstrated that tolerance developed at a similar rate to both heroin and morphine. When compared to the opioids hydromorphone, fentanyl, oxycodone, and pethidine (meperidine), former addicts showed a strong preference for heroin and morphine, suggesting that heroin and morphine are particularly susceptible to abuse and addiction. Morphine and heroin were also much more likely to produce euphoria and other positive subjective effects when compared to these other opioids. In the United States, heroin is not accepted as medically useful. Under the generic