This is a story about sex, drugs and Josh Homme. If you could regularly get that combination in your own life, you'd be living well. When they first emerged, Arctic Monkeys were writing songs that observed their generation with a squinting eye and a curled lip. Now they're living it. 

Unlike Oasis, arguably their prototype, Arctic Monkeys have kept moving and evolved as most of their indie peers have stagnated and fallen behind. This is in part because their influences came not just from The Smiths and Stone Roses, but also from hip hop, John Cooper Clarke and Alan Sillitoe. This gave a sense that the Arctic Monkeys are rooted in a very British experience, with broad tastes that elevated them above the lad hordes while enabling the development of their own aesthetic.

They've also managed to avoid many of the pitfalls that did for Oasis. In the early rush of their success, it was clear that Arctic Monkeys were neither comfortable with their fame nor able to really capitalise on it. They treated interviews with bemusement and barely phoned it in at awards ceremonies, yet it wasn't smugness or aloofness, nor an affected "ordinary blokes" act.

Early albums Whatever People Say I Am, That's What I'm Not and Favourite Worst Nightmare were the work of a band still in the grip of adolescence. Like Eric Hobsbawm's long nineteenth century – stretching from 1789 to 1914 – modern teenagerdom ends up drawn out. Most people don't shake it off until they're 25, or even later. Arctic Monkeys had a catalyst to speed up the reaction, to fizz them into a darker, groovier place. That catalyst was named Josh Homme, and as burly midwife for 2009's Humbug he helped get these adolescents in touch with their hairier, hornier, harsher core. 

If 2011's Suck It And See was a sweet treat for fans, AM is like finding your popping candy has been mixed with amphetamine. Hints of the band's love of hip hop had been scattered in basslines, drum beats and lyrics since their debut, but on the new album they've finally come to the fore. 'R U Mine' arrived with the kind of bassline Dre would happily sample the shit out of, and then came 'Why'd You Only Call Me When You're High?', which has enough swagger to make a young LL Cool J jealous. 

AM is a record of late nights and drinking. It's a galaxy away from the simple jealousies of an early b-side like 'Bigger Boys And Stolen Sweethearts'. This is an album made by men in their late twenties, men who are still trying to get a handle on all the fun they can have and all the disaster it can cause. For instance, the subject of 'Arabella' sounds like naughty sort: "Arabella has some interstellar ‘gator skin boots and a helter-skelter in her little finger and I ride it endlessly…" [surely Turner is singing the joys of a prostate tickle here? - ED] The tale is driven along by Josh Homme guitars and a sinister groove. 

Across AM you constantly brush up against the sound of a band unafraid to mess with the template, to call in friends to throw guitar onto track - as with the contributions of hugely inventive former Coral guitarist Bill Ryder Jones - while elsewhere Homme and Peter Thomas also play sidemen. If the mooted prospect of Haim doing the backing vocals had come to pass it would have been sweet icing on an already delicious thing. Still, Turner, Helders, Cook and O'Malley make a great fist of the high harmonies on their own. 'One For The Road' is cut-and-shut off Queens Of The Stone Age-style rock menace, the vocals near falsetto. 

Similarly surprising vocal takes abound on 'Mad Sounds', which throws them singing low in a bustling mix of guitar, doo-wop backing vocals and references to the Rolling Stones' '2000 Light Years From Home'. The same "shoo wop shoo wops" are found on 'Fireside'. Someone had a barbershop compilation in the studio! 'Snap Out Of It' has clicks, claps and the kind of catchy hooks that'll get you a job pumping out new songs for Icona Pop. Pleasing new lyrical conceits seem to float out from the bundle of sounds with every listen. Alex Turner throws out more bon mots in one track that most bands manage on a whole record. 

Though hip-hop and R&B are the most striking influences on AM, the tang of rockabilly and 50s crooners that weaved through previous Arctic Monkeys albums is also there. 'No. 1 Party Anthem' – a bit of a Katy Perry title – has crooning written through it like a stick of rock - all that hanging out with Richard Hawley and Turner's busman's holiday in Last Shadow Puppets has had a lasting effect. Similarly, on 'I Wanna Be Yours', the band's reading of John Cooper Clarke's 1984 poem – older than all the band members – turns the fast syllable splat into a slinking seduction. It's an honour that Clarke richly deserved.

But of all the songs and moments on AM that signpost the inventiveness and evolution of Arctic Monkeys, it's the seedy slink of 'Knee Socks' that is most striking. The penultimate track on the record, it begins as a enjoyable stomp but curls and collapses in on itself, descending into an R&B-influenced breakdown in the middle that recalls close harmony groups like BlackStreet more than any indie band of the past 30 years.

Alex Turner has gone from the clever boy who could spin a great chat up line to a man with what a former flatmate of mine called "throw down". Proper drugs and dirty sex have set the demonic heart of the Arctic Monkeys and boy howdy, that's a cause for celebration. Now, I'm not for a moment suggesting that Alex Turner is diving into naked Jenga every night and taking more drugs than a touring funk band – as Mclusky sang it – but if he is, he's shagging the right people and taking the right drugs. 

The sexuality at the heart of AM is best typified by what could be called the Question Song Trilogy: 'Do I Wanna Know?', 'RU Mine?' and 'Why'd You Only Call Me When You're High?' Whether or not the band deliberately created the trio of questioning songs or came to them by accident, they share key ingredients – lyrics with more cheek than a walrus in hot pants, heavy, hip-hop influenced basslines, and riffs so huge you'd need professional climbing gear to scale them. The Arctic Monkeys have comprehensively slaked off their PG-13 pretensions and gone full-on X-rated.