The Australian actor, who has been in and out of a psychiatric ward since attacking his former girlfriend Rachael Taylor in a Rome hotel last year, said that he has been battling "manic depression and severe OCD" for the past ten years.
In an exclusive interview, Newton told the Nine Network's A Current Affair: "Manic phases for me can be self-destructive [with] self harm, panic [and] confusion. It's like you've got a stereo on in two corners and you're standing in the middle of the room. It's all clashing together. Everything rushes forward and you have no control of your thoughts or actions."
He revealed that when he used to have "chaotic frenzies", he would "run at walls [and] bash [his] head against floors" and has shattered a bone in his eye socket, dislocated his jaw and severed tendons during the incidents. He explained: "It's like you want to rip your brain out of your head, wash it clean and put it back in your skull."
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Newton described the incident when he assaulted ex-girlfriend Brooke Satchwell in 2006 as "a complete breakdown", saying: "I was losing my mind. I was in such a state [that] they sectioned me. I utterly regret it." He also said that he hasn't spoken to her since.
He also spoke about when he slammed Taylor's head into a marble floor at a Rome hotel last year, saying: "[It was a] total meltdown, chaotic. It all just collapsed on me and I went berserk. I wanted to kill myself - I'd had enough of the noise. I'm ashamed about it."
Since leaving Northside West Psychiatric Clinic earlier this year, Newton takes "six or seven tablets in the morning and then a couple at night", but said that he is feeling the strongest that he has ever been and is "a lot clearer" in his mind.
The actor said that he is a "different person" since being diagnosed, adding: "I'm committed to being the best person I can possibly be and that's all anyone can guarantee.
"I've been given and shown great love and the people that are closest to you when you're in the chaotic frenzy of a manic episode - the closer they are to you, the more they get harmed."