His issue was activated by prescribed medications he took for accidents on the set of the 2006 smash hit 300, it's claimed on web page TMZ.com.
It is believed to have increased during the shooting of his new film, Of Men And Mavericks, when he experienced another damage in a browsing incident in December.
Sources say that the celebrity, 41, who has formerly discussed his battle with liquor, was also being handled for concerns with pharmaceutical — although the inherent issue is pain relievers.
It was unveiled that he decided to search for help before the issue got out of management, understanding he was beginning to depend on the prescribed pharmaceutical.
Gerard quit the liquor addiction after discovering his behavior went out of management in his beginning 20s, and damaged his prospective for a law profession.
He said: "I had gone from a 16-year-old who couldn't delay to understanding lifestyle, to a 22-year-old who didn't care if he passed away in his rest.
"I used to consume until I couldn't keep in mind anything. I was just mad for it and on a loss of life wish. It was chaos."
And then added: "One or two liquids was never enough for me. I was a foot-on-the-floor-all-the-way wine-drinker, so it had to go. I don't neglect it. Now it's as if I never had a consume in my lifestyle. At one factor, I could never have created going out and not consuming but, in the future, you drop the desire and the uncertainty that often creates individuals consume in the first position."
He is predicted to depart the California clinic today.
