Background and release
In 2006, after finishing high school, Tove Lo formed a math rock band called Tremblebee, with whom she played "shitty bars" across Sweden until 2009. When the band split up, Lo started to produce and write songs by herself, but in a "more pop" direction. While performing at an event in Stockholm in 2011, the artist met an English A&R who got interested in her work. After a meeting in which she played some of her demos, Lo signed a publishing deal with Warner/Chappell Music. This was followed with her joining songwriting teams Xenomania and Wolf Cousins. The deal led her to write songs for Girls Aloud and Icona Pop. During that time, she was going through hard times during a relationship, so she decided to avoid writing songs about that matter. At one point, however, she "could not handle it anymore" and started to write tracks related to her situation.
As of September 2012, Lo had released three songs on her SoundCloud account: "Love Ballad", "Evil Spawn" and "Paradise". The following month, the artist independently released "Love Ballad" as her debut single, which gained attention from music blogs. This encouraged Lo to pursue a career as a singer in order to keep her most personal songs to herself. In March 2013, the artist released "Habits" as her second single. It received a larger attention from publications, which led her to sign a record deal with Universal Music. On 16 October 2013, Lo released her first single through the label, "Out of Mind". In December of that year, she told Coup de Main Magazine that she was working on her first extended play. In February 2014, the artist announced that her first EP would be called Truth Serum and that it would be released on 3 March 2014. Neon Gold issued a limited 10" vinyl release on 4 March for the United States, while Polydor released the EP in the United Kingdom on 7 April. Universal Music released a 12" vinyl in Sweden on 21 April 2014. The Swedish version and the vinyl editions included "Love Ballad" as the opening track. On 23 September 2014, the EP was re-released, featuring a remix version of "Habits (Stay High)" by Swedish DJ Oliver Nelson and three out of the six original tracks.