Depp sued his ex-wife in March, accusing her of harming his career by penning a Washington Post article alluding to domestic violence allegations she made against him in 2016 during their explosive divorce.
The "Pirates of the Caribbean" star claims the article defamed him by alluding to the allegations, and is suing for $50 million, claiming the "Aquaman" actress's allegations were a deliberate "hoax."
Heard's lawyers, who are now led by Roberta Kaplan, have sought to have the case dismissed, but Kaplan claims that past records of alleged substance abuse and arrests will help prove Heard's claims in court.
"Ms. Heard has already testified that it was almost always drugs and alcohol that fueled Mr. Depp's abusive behavior and this is consistent with multiple accounts of his drug-fueled rages over many years," Kaplan said in a statement to Variety.
The two sides have also been unable to reach an agreement on a protective order that would stop information turned up as part of the discovery process being made public - as Depp's lawyers have said they want the "objective facts" of the case placed in the public domain.
Depp's lawyer, Adam Waldman, told Deadline.com the attempt to obtain records of past drug use and arrests were part of an attempt to smear the star "with additional false innuendo" as the case would prove her domestic violence claims are false.