Former Theranos Inc. CEO Elizabeth Holmes may use a "mental disease" defense in her upcoming criminal fraud trial, according to court documents.

Holmes, whose now-defunct biotech company was once valued at $9 billion, was indicted with the company's former COO Ramesh "Sunny" Balwani in June 2018 on wire fraud charges. The indictment alleges the pair duped doctors and patients and engaged in a multi-million dollar scheme to defraud investors through their Silicon Valley blood-testing startup.

Both Holmes and Balwani pleaded not guilty and could face up to 20 years in prison.

A court ruling on Wednesday will allow prosecutors to examine Holmes, which comes in response to the attempt by Holmes’ defense team to "introduce expert evidence relating to a mental disease or defect or any other mental condition of the defendant bearing on ... the issue of guilt."

Federal prosecutors will be able to have Holmes examined by a psychologist and a psychiatrist chosen by the government for 14 hours over two days. Despite objections from Holmes’ defense, the examination must be recorded on video.

The insanity defense is rare in such cases.

“Contrary to what you may see in the movies, an insanity defense in federal cases is rare and hard to fake,” said Barbara McQuade, a former federal prosecutor, told Bloomberg News in an email. Holmes must show that, at the time she committed the alleged offenses, a severe mental defect made her “unable to appreciate the nature and quality or the wrongfulness of (her) acts.”

Due to the coronavirus pandemic, Holmes’ trial had originally been set for the summer but was postponed to March. Balwani will be tried separately.

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