When you're kicking 'lean', you deserve some leeway if you find yourself in a funk. A concoction popularised in Houston, Texas, its promethazine offers that 'dissociative' feeling and high levels of codeine leave you euphoric. As you can imagine, your body doesn't want to let go of that feeling without a fight. Last summer, magnificently talented Detroit MC Danny Brown found himself waiting for his label, Fool's Gold Records, to drop his third album Old. In between worrying that the record might "never come out" and publicly threatening to leak it, he developed quite the habit. "I'd finished the album way before I started drinking lean a lot," the rapper says, sitting backstage in Dublin's Academy. "So then once it was done I didn't really have anything else to do! I had a lot of time on my hands, aside from doing shows. I was just sitting around drinking. It was probably that that caused the depression more so than me sitting around waiting on the actual music."
On January 17, he wisely decided that the lean had to go. Unlikely to ever knock everything on the head, he'd still rather not end up dead. Choosing a European tour to go cold turkey presented its own problems. In the run-up to our chat, he'd walked out of a Guardian interview (due to a row over… a scotch egg) and been rude and unresponsive to another journalist (later apologising after reading how disappointed she was online). He'd posted worryingly suicidal comments on Twitter.
It's a relief to see Danny, fresh off the Irish ferry, tweet: "No more withdrawal symptoms anymore .... Life is great now bruh bruh glad I got over that chapter in my life." Sure enough, he's in excellent form when we meet in the evening; easy with his trademark gap-toothed smile, an open and charismatic character. "I been good for a minute now but I was still going through crazy mood swings and shit," he admits. "But now I think I'm through it. Just waking up feeling alright."
He's pleased to be on this side of the Atlantic. Not that you'll find him sight-seeing – "I'm on tour, I'm not a tourist" he chuckles – but he's always had closer musical ties to the likes of London than many US artists, citing Dizzee Rascal's Boy In Da Corner as a formative listening experience. He feels European crowds are more about the music. "They don't care about any of that extra shit. Like back home, there's so much shit, people don't care about it. They just go to the show cos they know there's gonna be girls there!"
Regarding Brown's libido, he went from getting oral relief from a female fan on stage last May to telling Pitchfork in September that he was now rejecting girls in favour of going back to his hotel room to watch cartoons on TV. He laughs like a drain. "I think that was me in my leaned-out phase! After that, I'm a little more 'up' now. I might go back on my word!"
The small screen's been a draw in other ways. Gamers will know that Brown and Action Bronson contributed 'Bad News' to the Grand Theft Auto V soundtrack, but they might not be aware that Brown also starred in the hugely successful title, voicing a particularly pissed-off lifeguard. Was appearing in the GTA series a big deal?
"Hell yeah it was!" he exclaims. "They brought me in to do music; that was the first meeting. And I was like 'man I don't want to do music, gimme a voiceover! Let me get a character.' Just bossed up like that. DJ Cool was handling that at the time, so you had to go through him. Then the music started taking off a little more so they called me over. They wanted me to come up with my own shit, but I was so nervous – not nervous, just that I couldn't believe that I was doing it. I said, 'I''ll just read the script, whatever you got.' I wish I'd came up with my own shit because I wouldn't say 'Imma make it rain on you boo'! I wouldn't say none of that. [The character is] an ex-football player that's a lifeguard now and a coke head."

How would he handle lifeguarding duties in real life?
"I can't swim man, black people don't know how to swim! Black people in Detroit, particularly. There ain't no beaches!"
Well if he fancies a foray into film, that could be just the comedic vehicle for him: Danny Brown IS The World's Worst Lifeguard.
"Yeah that might be tight," he says, seeming to give it serious consideration. "A movie about the worst lifeguard ever! Muthafuckas dying on him. A shark coming in and me just going 'oh shit, it's a shark!' Watching the shit! That could be some Anchorman shit, but with lifeguards. We need to get Will Ferrell my script! Thanks for that idea, cuz."
More than welcome. Thus far, Brown's onscreen, in-person appearances have mainly been confined to chat shows. Brown and A$AP Rocky didn't look particularly comfortable during a particularly chaotic Kathy Griffin appearance, where it was left to Russell Brand to take control over the conversation (shockingly, Russell was only too happy to oblige).
"I was nervous," he admits. "And I also drank lean that day too. So I was… y'know. I had to drink it to calm down because I was super nervous about being on live TV. With Kathy Griffin, you don't know what the fuck she's gong to do! I was thinking this could be bad or this could be the best thing ever...
"Russell Brand held us down, if he wasn't there I don't know what we would have done. The both of us were [having] out-of-body at that point! We didn't really care to be honest. Russell did help us out. If he wasn't out there I feel like I woulda had an anxiety attack. Live TV? That's crazy! Everybody's watching this shit now?! Crazy."

Are interviews his least favourite part of what he does?
"No, it's just like rappers. Some of them [journalists] are really good and some of them are bad! That's all it is, it's like anything. You're pretty good at it, you're cool! Questions are questions at the end of the day but you do feel like you're getting interviewed by the police or something. I dunno, I just don't really wanna snitch!"
A beat.
"I'm the best rapper on the planet... Who cares?"
Plenty of people, as it turns out. It's a big statement, but he went a long way to backing it up with Old. A tour-de-force tracing the history of hip-hop, it cements his position as one of the most unique voices out there. At 33 – fairly ancient in rap – he's taken his time. "It's not a sprint," Brown says. "It's a marathon." Of last year's releases, he reckons only Kanye West's Yeezus could go up against his own. "Just because of how it sounded. He has fucking million dollar mixes, y'know?! So you can't really compete with that. But I love anybody that just cares about music and he's one of the people that cares about music the same way I do. So yeah, I'm a fan of Kanye."
Someone who grew up devouring music magazines, Brown waxes lyrical about Love's Forever Changes and venerates artists who create their own universe. When I suggest his eclectic tastes have led some writers to patronisingly paint him as "wacky", he coyly notes: "I think it's other stuff that goes into it that makes people say stuff like that… But, for the most part, being a music nerd doesn't make you weird! I'll take 'weird'. I just smoke it like a motherfucker, it ain't no fire!"
Dizzee Rascal and Nas are two artists that take him somewhere else. "They were talking, being very detailed, about a place I've never been. When I listen to those albums I can close my eyes and feel like I'm in that place. Queensbridge Projects, listening to Illmatic. Bow, listening to Boy In Da Corner. Chief Keef makes me feel like I'm in Chicago. I want to sit them right in the kitchen in Detroit. I want to sit them right where I'm at!"
For the first time in a long time, that seems a pleasant place to be. The next step is "living, creating stories", but there's no masterplan in terms of an Old follow-up. "I don't make music with my brain, I make it with my heart." He pauses. "I probably do a lot of things with my heart instead of my brain actually!" Another hearty laugh. Another tweet from Danny Brown in Dublin: "Now I can concentrate on what matters most and that's delivering the best music I can possibly make and I promise I won't let anyone down."