Thematically, the song is about heroin addiction, though lead vocalist Bono has given varying accounts of who was the inspiration behind his lyrics.
A live version of the song appears on U2's 1985 EP Wide Awake in America; this rendition became popular on album-oriented rock radio stations.
"Bad" originated from a guitar riff that the Edge improvised during a jam session at Slane Castle, where U2 were recording their 1984 album The Unforgettable Fire.
Of its immediate and live nature, the Edge said, "There's one moment where [drummer] Larry [Mullen Jr.] puts down brushes and takes up the sticks and it creates this pause which has an incredibly dramatic effect.
His account from a 1987 concert in Chicago during the Joshua Tree Tour indicate "Bad" is about a friend of his who died of a heroin overdose and also about the conditions that make such events likely to be repeated.
Bono once commented in another concert (in the UK) about people lying in gutters with "needles hangin' outta their fuckin' arms while the rich live indifferently to the suffering of the less fortunate."
'"[8] During a 26 July 2011 concert in Pittsburgh during the U2 360° Tour, Bono introduced a performance of "Bad" as a song written for a "very special man, who is here in your city, who grew up on Cedarwood Road.
Translating the elaborate and complex textures of the new studio-recorded tracks to live performance proved to be a serious challenge when the Unforgettable Fire Tour commenced.
[11] The studio version of "Bad" was criticised as being "unfinished", "fuzzy" and "unfocused", but the band found that it made more sense on stage.
These snippets are typically sung after the line "I'm not sleeping" and Bono has included up to six different excerpts in a single performance of "Bad".
[14] They played a 12-minute version of "Bad", which was extended by snippets of Lou Reed's "Satellite of Love" and "Walk on the Wild Side", and The Rolling Stones' "Ruby Tuesday" and "Sympathy for the Devil".
[19] "Bad" is the first track on the 1985 EP Wide Awake in America, this being a live version recorded at Birmingham's NEC Arena on November 12, 1984 during sound check.