(NewsNation) — Boxing legend Mike Tyson praised President Donald Trump’s reclassification of marijuana, calling it a “game-changer” in his own life.

Under an executive order signed Thursday, Trump reclassified marijuana from Schedule I to Schedule III under federal drug law, putting it in the same category as prescription pain medications and other substances that have a recognized medical use with lower potential for addiction.

Tyson, who said he has smoked marijuana since the death of singer Tupac Shakur, told “CUOMO” his “life has changed completely.”

“It was good for my mind. I was absolutely crazy at one time because I was drinking all the time. Since it was legal, it seemed like it’s not a problem. It was acceptable,” Tyson said. “But I was a mess back then. Since I started smoking, I’m who I am. I’ve become very successful.”

While Tyson acknowledged a stigma remains around marijuana use in the U.S., he said Trump’s order is a major step toward normalizing it.

“I’m a believer, and so is the president,” Tyson said. “This is old-fashioned thinking, that you’re going to go crazy or go into an insane asylum. Man, I know it will help. I know it will help a lot of people, because it helped me and helped many other people that I’ve been acquainted with.”

Moving forward, Tyson said he’d like to see additional federal rules on marijuana use.

“We do need standards. It has to be like alcohol. You can’t drink in front of a school or a library, and it’d be the same way with cannabis,” he said. “My main objective is to get these people that’s in prison for the cannabis crimes, got 10, 15 years, and I want to get clemency for those guys. You know, anybody that has a nonviolent cannabis crime, I want clemency for them.”