Simone Biles couldn’t bring her ADHD medication to Tokyo, and it may have impacted her ability to perform

• Simone Biles withdrew from both Olympics all-around finals due to mental health concerns.
• The superstar gymnast later said she's experiencing "the twisties," which cause disorientation.
• Biles takes ADHD medication disallowed in Japan and may be feeling the effects of not having it.
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Simone Biles has been struggling with her mental health in Tokyo, prompting the superstar gymnast to pull out of both Olympics all-around finals.

While the withdrawal of the biggest star at this summer's games was a shocking development at the time, perhaps Biles' health battle shouldn't be so surprising.

Biles has ADHD, and it appears she hasn't been able to take her medication in Tokyo.

An illegal release of some high-profile athletes' medical data back in 2016 revealed that Biles had tested positive for methylphenidate – better known as Ritalin or Adderall. The situation forced the then-19-year-old star to publicly address her ADHD diagnosis and explain that she's taken the medication since she was a child to manage her symptoms.

"Having ADHD, and taking medicine for it is nothing to be ashamed of," Biles wrote on Twitter at the time. "Nothing that I'm afraid to let people know."

-Simone Biles (@Simone_Biles) September 13, 2016

-Simone Biles (@Simone_Biles) September 13, 2016

Ahead of the 2016 Rio Olympics, Biles had filed for a "therapeutic use exemption" through the World Anti-Doping Agency, enabling her to continue taking the drug throughout her breakout competition. But this time around, in Tokyo, Biles was not granted access to her much-needed medication.

According to the Associated Kyoto Program - a non-profit that facilitates travel between the US and Japan - "all medications containing stimulants are prohibited" in the country.

"This includes Adderall, a standard medication used to treat ADHD symptoms in the US," the AKP website reads. "If you bring Adderall into Japan for any reason, you risk arrest and imprisonment... While Ritalin is available in Japan to treat sleep disorders, it is not prescribed to ADHD patients."

The laws in Japan likely left Biles with little choice but to forego her prescribed medication while abroad for the games. And while it's impossible to determine what exactly has caused Biles' case of "the twisties," it's difficult to imagine that a sudden withdrawal from the drug she's taken for years did not work against her.

Biles is still eligible for the remaining four women's artistic gymnastics events in Tokyo, though it remains unclear whether or not she'll participate. Her next chance to get back into the gym is on Sunday for the vault final. The balance beam, floor, and uneven bars finals - all of which Biles has qualified for - will take place later in the week.