Songfacts®:

• This is the opening track from Delirium, an album that is based around the concept of a mental hospital, with each song being a different story told from a patient's perspective. Co-vocalist Andrea Ferreo explained to TeamRock: "It's probably the most catchy song on the album because it's just repeating the word 'delirium' over and over – that's actually where we got the title from. We wanted to have something that fit in the melody of the song that also made sense to the record, and that's what we decided on."
• The song was inspired by a friend of Andrea Ferreo's mother. He said: "She's super-intelligent but at times lost it because her brain can't handle it. She refused to take her medication and ended up having the police break her out of a hotel room. It just showed me how quickly you can lose someone. It isn't written from her point of view, but she was in my mind when I was writing the lyrics."
• "Delirium," meaning wild excitement or ecstasy, was originally a Latin word from the verb "deliare" ("deviate; be deranged") The literal meaning was "deviate from the furrow." A "delius" was thus a person who could not plough straight and was, therefore, crazy.
  
  Other artists that have penned songs with the word "delirium" in the title include Ladyhawke, Coheed and Cambria, Motion City Soundtrack, MGMT, Yes and Ellie Goulding.
• Co-vocalist Cristina Scabbia explained to Blabbermouth how the video was shot: "We filmed our parts for this video in one evening while we were on the US tour this past May. We used a Go-Pro against a black backdrop and we wanted something that would be purposely rough, something that could remind some weird lost videos found after years and years."
  
  "The whole video edited together with the parts filmed by the director with an actress turned out as a very strange sort of a trip, where a girl tries to tight up memories and details together to try to find her sanity back, somehow. I really like some of the scenes as they reminded me some kind of Korean horror movies vibe and it is totally fitting the Delirium vibe and concept. It also leaves a lot to the imagination."