The singer and actor, 37, said the condition “sort of runs in my family” and that she was only recently diagnosed with it.
She previously suggested that she had been diagnosed with ADHD, alongside other mental health issues including post-traumatic stress disorder (PTSD), postnatal depression, and bipolar disorder.
In a new interview, published today (Saturday 1 April), Allen said she was unsurprised by the diagnosis of adult ADHD. Adults with ADHD may struggle with impulsiveness, restlessness and difficulty paying attention.
Speaking to The Times, the “F*** You” singer said: “I’ve had to completely switch off social media because as soon as I look at it, it can be hours of my day gone.”
She added: “It sort of runs in my family. And it’s only because I’m here in America where they take these things slightly more seriously than they do in England.
“I went to see someone and they said, ‘Have you ever thought about this?’ And I said, ‘Well, yes I have’.”
Allen said that acting has allowed her to become more “disciplined”, which is “a completely new thing for me”.
“I think it’s a combination of age and being able to take responsibility and genuinely being fascinated and grateful for these opportunities, which I know so many people have been working towards their entire adult lives,” she continued.
The Dreamland star also credited her recent success in acting to her sobriety, adding that she has been “sober for nearly four years”.
In 2021, Allen spoke in detail about her addiction to prescription drug Adderall in 2014.
The drug is a prescription-only medication used to treat ADHD, but Allen wrote in her memoir My Thoughts Exactly that she used it “as a way of getting or staying thin”.
In an appearance on The Recovery podcast with host DJ Fat Tony, Allen said she started taking the drug when she was trying to lose weight for Miley Cyrus’ Bangerz Tour, which she was supporting.
“I was like 14 stone and just did not feel like a pop star at all,” she said. “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.”
Allen also opened up about drinking and “acting out” during the tour, which took place after she had spent “the last three years pushing babies out”.
“It was when [Cyrus was doing Wrecking Ball and the Bangerz tour and it was a highly sexualised tour… It couldn’t have been less what I felt like,” she explained.
“I started cheating on my husband and I had always really drunk alcohol to take the edge off of the drugs, and then I realised I was getting up in the morning and downing those mini bottles of vodka or whisky or whatever was left, without the drugs anymore.”
She decided to get sober in 2019, and has since starred in West End show 2:22 A Ghost Story and Dreamland, and is set to star in The Pillowman this summer.