It was just a guess based on the half crying monologue she delivered at the start of the performance.
Quote:
Following her hip surgery and cancellation of the Born This Way Ball tour, Gaga became addicted to drugs, which helped her get relief from the pain of surgery and also to cope with her sabbatical. "Dope" was written about this addiction and was the evolution of fan song, that gradually turned into a personal confession for the singer. It was added to Artpop because Gaga felt the album needed something more autobiographical.
