By mixing true-life confessions with a sociopathic, hip-hop alter ego, Eminem sold millions of records.

In late December 2007 a depressed, opiate-addicted Marshall Mathers, better known as the multimilllion-selling rapper Eminem, overdosed on methadone and collapsed on his bathroom floor. After a stint in the hospital, Mr. Mathers resumed his drug habit within a month.

But the overdose scared him. Early last year he hospitalized himself, went through rehab and started the full 12-step program of a recovering addict. Mr. Mathers, 36, says he has stayed sober since April 20, 2008.

Far from concealing his addiction battle, he’s making it the center of his comeback. The cover of “Relapse” (Shady/Aftermath/Interscope), the first new Eminem album since 2004, builds his face out of pills, and in some songs he raps, as directly as a rhymer can, about how drugs nearly destroyed him. Elsewhere on the album Eminem resumes - or relapses into - his main alter ego, Slim Shady: the sneering, clownish, paranoid, homophobic, celebrity-stalking compulsive rapist and serial killer who plays his exploits for queasy laughs and mass popularity.

Eminem’s four previous major-label albums of new material have sold about 30 million copies in the United States, according to Nielsen SoundScan. “Relapse” clings to the formula of its predecessors: it’s partly truth and partly fiction, with personal revelations and sociopathic farce side by side.

“It’s hard core, it’s dark comedy, it’s what Eminem has always been,” said Dr. Dre, his longtime producer.

“Relapse” is the latest episode in a theatrical career that has always mingled confession, melodrama, comedy, horror, media baiting, craftsmanship and tabloid-scale hyperbole on every front.

“I don’t know if I’m exposing myself,” Mr. Mathers said by telephone from his studio in Detroit. “I’m kind of just coming clean and exhaling.”

He speaks amiably and coherently, without defensiveness. “I was so deep into my addiction at one point,” he said, “that I couldn’t picture myself being able to do anything without some kind of drug.”

But last year, just two months out of rehab, Eminem met Dr. Dre in Orlando, Florida, to try recording. Eminem had been doing what he called “mind exercises” to get himself writing. “I’d stack a bunch of words and just go down the line and try to fill in the blanks and make sense out of them,” he said. “For three or four years I couldn’t do it anymore.”

When he was sober, he said, “the wheels started turning again.” Working in Orlando and then in Detroit, Eminem and Dr. Dre recorded hundreds of tracks and finished enough new songs for three albums. They have culled them to two; Eminem plans to release “Relapse 2” before the end of this year. “The deeper I got into my addiction, the tighter the lid got on my creativity,” he said. “When I got sober the lid just came off. In seven months I accomplished more than I could accomplish in three or four years doing drugs.”

From the beginning Mr. Mathers has smeared the boundary between Eminem and Slim Shady. In “97 Bonnie & Clyde” from the 1999 “Slim Shady LP,” the rapper takes along his gurgly baby daughter - named Hailie, like Mr. Mathers’s real daughter (who lives with him in Detroit) - while disposing of her mother’s murdered corpse. The new album traces Eminem’s addictive tendencies to one of his most frequent targets: “My Mom,” who, the song says, used to mix Valium into his food to make him manageable.

But the music for songs like those is reassuring, even perky. That smiley-faced nastiness was enough to make Eminem a target for the censorious, which gave him new antagonists to provoke.

Now, a decade into his major-label career, “I’m done explaining it,” he said. “Here’s my music. Here’s what it is. Get what you get from it. I didn’t get in this game to be a role model.”