For heroin to be a drug that a touring alternative rock musician could be addicted to and then overdose on, it requires an international supply chain. Someone has to grow the poppies, someone has to process the poppies into heroin, someone has to distribute it to users. This is a risky business at all parts of the chain because there are international treaties that strongly control illicit drug supply (I discuss the rise of these treaties here using marijuana as an example here); typically this means that it's states that are international pariahs, failed states, and areas of a state that aren't actually under that state's control where you will find the poppy fields that supply the heroin trade. In the era of the Vietnam War - the era of John Lennon's 'Cold Turkey' or Janis Joplin's overdose - the world's heroin supply largely seemed to derive from Cambodia and Laos, and the CIA appears to have turned a blind eye to this because the heroin money benefited local rebels they supported. Similarly, during the 1980s Soviet-Afghan War, the CIA infamously supported fundamentalist Islamist groups like the Taliban against the dreaded Communists, and the mujahadeen extracted a 'poppy tax' from areas they controlled. After the fall of the Soviet state in the late 1980s, the Afghan state collapsed, controlled by local warlords who found that poppy production was effectively a very lucrative way to fund their wars against other local warlords. As a result, poppy production in Afghanistan allegedly went from 250 tons in 1981 to 2500 tons in 1990, and increased towards 4600 tons in 1999, providing a large proportion of the world's illegal heroin supply along with Myanmar/Burma. So the turn of the 1990s was certainly a period when heroin was becoming more widely available.

There was also a noticeable increase in unemployment in the early 1990s in many countries in the West, and that unemployment seemed quite centered on young people. From early 1990 to mid-1992, unemployment spiked from 5.2% to 7.8% in the US, while unemployment spiked from 6.9% in the UK in early 1990 to 10.7% in the winter of 1992/1993 in the UK. Much of this unemployment was youth unemployment; in the UK, for 18-24 year old males, unemployment was 21.5% at its peak in early 1993.

So the early 1990s was a period of both increasing supply of heroin, thanks to Afghan warlords, and increasing demand for heroin, thanks to all the unemployed young people, many of whom would have been feeling a mix of hopelessness, boredom, depression, anger, and worthlessness, and who would have welcomed heroin's ability to dull the emotional pain for a while. This became a social problem in the UK in the 1990s, which led to increased burglaries as other crime indicators generally fell down (heroin users turning to theft to fund their drug use). 'Heroin chic' also was a thing in the early 1990s; Calvin Klein ads of the era featuring Kate Moss were criticised for her emaciated appearance, while the references to heroin in the music of the era speak for themselves. Movies like Pulp Fiction (1994) portrayed heroin use and overdose relatively matter-of-factly rather than in a heavily moralised way. A 2008 paper by Bryan Denham argues that there was a moral panic in America over heroin chic during the early 1990s (Denham argues that the moral panic was unjustified and heroin use hadn't changed during the heroin chic perod, but I'm dubious about this argument given the rising levels of Afghan poppy production, the unemployment of the era, the equivalent UK data, and Denham's time series data not being quite wide enough for my liking, though it's possible that US authorities were more effective at controlling the supply chain than in the UK, or simply geographically further away; Denham's paper is probably best seen as pointing out that the early 1990s weren't particularly special in terms of supply in context of their surrounding years).

Anyway, the early 1990s coincided - not coincidentally - with the height of grunge and alternative rock, a musical style that obviously traded on feelings of self-loathing and social discord in a way that was profoundly alien to middle-aged baby boomers. Songs with lyrics like 'I'm a creep, I'm a weirdo', and 'I'm a loser baby, so why don't you kill me' became hits. For alternative rockers, having some sort of past emotional trauma was a sort of badge of honour, and as a result, Rolling Stone and Spin were full of successful rock stars talking about the broken homes that they grew up in to try and bolster their authenticity as a representative of this lost generation - 'Generation X' - who seemed doomed to unemployment and who were seen as suspect in mainstream mass media, the way that millennials are now seen as suspect (I discuss grunge and Nirvana's success in more detail here and here).

Furthermore, people have this idea that the rock'n'roll lifestyle is all sex, drugs and rock & roll, all the time, that its parties and hedonism and instant gratification of desires. However - if I can get anecdotal for a second - a friend whose alternative rock band played the Glastonbury Festival in 1990 once told me "rock and roll is all about 'hurry up and wait'". Much of the lifestyle is peripatetic, with long periods of absence from one's emotional support network, and long periods of uncomfortable boredom sitting on tour buses with people you likely have spent too much time with. And it's a lifestyle where you lack control - things have likely been organised for you, and not always well. It's also not a lifestyle where, if you have a mental illness, you are typically able to have regular appointments with a psychologist or a psychiatrist who knows the ins and outs of your issues.

In such circumstances, self-medication with illegal drugs is quite common, and quite dangerous once the musician is addicted - that same peripatetic lifestyle (along with the illegal and thus unregulated nature of the drugs) also means that you don't necessarily have a regular stable supplier of the drug who is able to supply with the right amount of the drug for you, given your tolerances. Given that heroin is a dangerous drug, taking heroin that someone has given you in a new city is something of a lottery. Heroin overdoses are more likely to occur when the drug is combined with other drugs, or when it is taken in higher dosages than the body's tolerances can cope with, or when it is taken in unfamiliar settings - i.e., when your body is not expecting it and has not prepared your usual levels of tolerance. Touring musicians are more likely to overdose than the general population of heroin users for exactly these reasons.

So, to recap, in the early 1990s, both supply of and demand for heroin increased worldwide. Alternative rock musicians certainly lived in the kind of milieu where heroin would be available, and there were justifications for why they might take it (Kurt Cobain, for example, seems to have started taking heroin to manage chronic stomach pain). And because of the nature of their lifestyles, they were probably more likely to be exposed to the kind of changes in the chemical nature of the drug - or the setting in which they took the drug for that matter - which were likely to result in an overdose.

Great answer /u/hillsonghoods !

As a follow-up, how would someone like Phil Anselmo fit into this? He was of the same generation as the alt-rock musicians mentioned (he was just one year younger than Kurt Cobain), and he damn near died from his own heroin addiction in 1996; yet, the hypermachismo of his lyrics, music, and overall post-80s metal subculture was in stark contrast with the fairly open vulnerability expressed by his alt-rock contemporaries, and he probably was somewhat disdainful of them for that (although even he had expressions of frailty hidden amid his tough-guy screams of defiance, such as the two part "Suicide Note" on The Great Southern Trendkill). Can we analyze him in relation to the 90's alt-rock heroin culture with his odd combination of similarities to and contrasts with his alt-rock contemporaries?