Johnny Depp says he was “more inspired” to turn to drugs and alcohol because of the “constant clashes” between himself and former partner Amber Heard.

The actor, who is suing Ms Heard for defamation in a US court, said she had a “need for conflict” and “couldn’t be wrong”.

The libel case is being brought over a 2018 article the Aquaman star wrote in The Washington Post, which Mr Depp’s lawyers say falsely implies he physically and sexually abused her.

Much of the evidence heard so far at the trial, taking place in Virginia, has made reference to his use of substances while the two were together, which Ms Heard’s lawyers said have triggered violent episodes.

Asked if his consumption of drugs and alcohol had been affected by his deteriorating relationship, Mr Depp said: “Yes, I was more inspired by Ms Heard to reach out for a numbing agent because of the constant clashes.

“There wasn’t a day that she would wake up and you’d expect something would hit the fan, and pretty much like clockwork it did.

“I had to have something to distance me and distance my heart from those verbal attacks, I had to have something to be able to maintain me.”

Giving evidence for the second day in a row, Mr Depp said that over time his marriage to Ms Heard had begun to feel like he was “in a relationship” with his mother.

“Things started coming up and I was suddenly just wrong about everything,” he said.

“If you tried to explain yourself and correct the problem, the misunderstanding, it would then begin to heighten as Ms Heard was unable to be wrong.

“It just didn’t happen, she couldn’t be wrong.”

He added that “little digs” would escalate into full-scale, “circular” arguments.

“There’s no way in or out, if there’s a dialogue between two people, both people need to speak, but there was no way to fit a word in,” he said.

“It was a rapid fire, endless parade of insults and looking at me like I was a fool.

“At a certain point what enters your mind, you start to realise you are in a relationship with your mother, so to speak.

“I know that sounds perverse and obtuse, but the fact is that some people search for weaknesses in people, that is to say sensitivities.”

Mr Depp told the jury the “only ambition I’ve ever had in my life” was to be a good father, but that Ms Heard had told him on many occasions that this was not the case.

“One can only take so much of that before.. the valves get shut off because you can’t hear it any more,” he said.

Mr Depp wore a grey suit and light-coloured paisley tie and had his long hair tied back, and Ms Heard wore a light yellow blazer with her hair down.

The actress is also due to give evidence during the trial at Fairfax County District Court, which is set to last a total of seven weeks.