So one interpretation is that it's about a relationship, but in retrospect given Avicii's (Tim's) troubles with drinking and recent death --RIP :(, it seems likely that it's about a bad relationship with alcohol. Literally: "at the bottom of the bottle you're the poison in the wine". And "You're the high that I can't give up" is about addiction. Reported he felt lonely touring non-stop and filled the void by partying and drinking.
So one interpretation is that it's about a relationship, but in retrospect given Avicii's (Tim's) troubles with drinking and recent death --RIP :(, it seems likely that it's about a bad relationship with alcohol. Literally: "at the bottom of the bottle you're the poison in the wine". And "You're the high that I can't give up" is about addiction. Reported he felt lonely touring non-stop and filled the void by partying and drinking.