In a new interview, the 35-year-old said she had taken the drug in an effort to lose weight before supporting Miley Cyrus on tour.
“So I started taking this drug called Adderall, which is like speed, to lose the weight.
“And I got addicted to this drug because it made me invincible and I could work really long hours and be all the people I was required to be.”
It is not the first time Allen has discussed taking the drug, which is a prescription-only stimulant typically used to treat attention deficit hyperactivity disorder (ADHD).
In her 2018 memoir My Thoughts Exactly, the singer wrote: “I flirted with Adderall (which is really just a type of speed) as a way of getting or staying thin.”