Evan Dando’s autobiography opens in early 2021. The singer is living in a mouldering trailer on Martha’s Vineyard. He has a $200-a-day drug habit and is subsisting off a diet of cigarettes and cheeseburgers that he can’t chew because the heroin, cocaine and amphetamine he’s injecting have caused his teeth to fall out.

It’s all a very long way from Dando’s brief burst of fame as frontman and solitary longstanding member of the Lemonheads: two big albums in 1992’s It’s a Shame About Ray, and 1993’s Come on Feel the Lemonheads, a huge hit cover of Simon and Garfunkel’s Mrs Robinson, an era with Dando’s face taking its place alongside the Betty Blue and magic eye posters on halls of residence walls, the Docs-shod female student’s pin-up of choice. But it’s also not totally unexpected, at least if you have even a glancing knowledge of the singer’s subsequent travails. Mainstream success was short-lived: Dando succeeds in sabotaging his own career in a blaze of hard drugs and wildly unpredictable behaviour. For the last 35 years, drugs and unpredictability – rather than music – is what Dando has become known for. The book’s blurb mentions “heroin chic”, but in truth, Dando’s dissipation is almost impossible to put any kind of romantic gloss on. To his credit, he doesn’t bother, instead recounting one public humiliation after another with a what-can-you-do? shrug.

A cocktail of heroin and cocaine puts paid to a show designed to impress investors who’ve just bought a share of Dando’s song publishing for $300,000, but it’s just one of many gigs that collapse into chaos: he falls offstage, or the police are called and he’s led away from the venue in handcuffs. The Lemonheads miss their slot at Glastonbury because Dando is holed up in a hotel, doing heroin: when he does eventually turn up, he performs an unscheduled solo set, but the crowd throw bottles and boo him offstage. He hangs around Oasis in their pomp, even writing a song with Noel Gallagher: it has to be removed from a Lemonheads album at the last minute, because Gallagher deems it an “embarrassment”.

You start wondering what his problem is, but there aren’t any straightforward answers: there’s no great childhood trauma beyond his parents’ divorce, which he seems to navigate well, and a predisposition to sleepwalking, which he eventually overcomes. Indeed, you get the sense that Dando’s real issue may be that he’s never had to try very hard. His parents are wealthy and he’s educated privately at a school so liberal that the only rule involves not rollerskating in the corridors; they nevertheless try to expel him after the first year because of his disinclination to do any work, but his mum steps in and talks them round.

Long-haired and preposterously handsome, he works as a child model – his dad invests the money in shares, leaving him a tidy nest-egg – and from his teens onwards seems basically irresistible to women. When he forms the Lemonheads, consternation is caused by their privileged backgrounds but it doesn’t seem to impede their progress. They become increasingly successful as they shift from playing hardcore punk to melodic indie rock, garnering themselves a major-label deal, and eventually, international success. Understandably so: Dando has a genuine gift for songwriting. It’s a Shame About Ray lasted under half an hour, but every one of its 29 minutes contained a killer melody or a nagging hook.

He is uncomfortable with celebrity, particularly the magazines that drool over his looks, and unhappy about being catapulted to fame by a hastily thrown together Simon and Garfunkel cover. But he’s hardly self-medicating to cope with the pressure: he just seems to have really liked taking drugs from the moment he started doing LSD, aged 14, and saw no reason to stop when he became famous. He attempts to blame the press for sensationalising his narcotic habits, but, frankly, if you turn up to an interview to promote your new album with a pad and pen to write your answers down because a crack-smoking binge has left you unable to speak, what do you expect? He claims his record company lost faith in him when Come On Feel the Lemonheads didn’t outsell its predecessor, but again, it’s hard not to wonder if the whole smoking-so-much-crack-you-lose-your-voice thing might not have caused a certain dip in corporate expectations.

He sounds insufferable, but weirdly, he doesn’t come across that way in the pages of Rumours of My Demise. You wouldn’t want to be in a band with him, nor sign him to your label, but he’s a good writer, possessed of a laconic wit and, occasionally, bluntly insightful: “If I could go back in time and give a bit of advice to myself, I’d say ‘Evan, don’t be such a dick’.” The book ends with Dando kicking heroin – although a recent European tour was the usual chaos – and the reader finding Dando hopeless, but strangely charming with it: he’s somehow got away with it, as he seems to have done for the last 40 years.

• Rumours of My Demise is published by Faber (£20). To support the Guardian, buy a copy at guardianbookshop.com. Delivery charges apply.