"With celebrities, it becomes complicated," Sack said. "You can't take them into the community without the paparazzi chasing your vans and then you wind up with decoy vans and you sometimes feel like you're plotting a spy thriller rather than just taking people to treatment. Many of those clients will go out to other more private meetings with sponsors or what we call trusted servants -- our alums. "
For this, treating celebrities with kid gloves, Promises has become famous. It attracts addicts from around the world and frequently turns away would-be clients to avoid overfilling its facilities (Malibu's capacity is 36 clients; L.A.'s, 18). Meanwhile, Promises' programs are expanding. Last year, as pro golfer Tiger Woods sought treatment for sex addiction, the center established a partnership with L.A.'s Sexual Recovery Institute and its founder, Rob Weiss, who hopes that eventually, people in the public eye will tout the powers of sex addiction therapy the way they back AA's 12-step program.
"It's a lot harder to say that you have a sexual problem," he said. "It's much more personal, much more shameful. Culturally, it bears a lot of weight around morality and sin. We don't have figures standing up and saying, 'I have this problem.' It would have been nice had Tiger come out of treatment and said 'Wow, this really changed my life and I'm glad I did it, but unfortunately, he's not saying anything about the issues.'"
But treatment, no matter the type, doesn't always stick. Lohan and Sheen graduated Promises only to spiral down again spectacularly. Fellow alum Danny Bonaduce told ABCNews.com that Promises did nothing for him.
"They charged me more than $40,000 for my stay and I drank on the way home," he said. "But Malibu was beautiful. I remember thinking that if this place had a bar, it would be fantastic."
In his recent spate of interviews, Sheen also wrote off rehab as "fiction" and dismissed AA for its "five percent success rate." (He sang a different tune in a 1999 interview with ABC News, saying Promises taught him "about taking the power back, that there is a better way. You don't have to live like you did anymore.")
While Sack said Promises is "currently collecting data" on rates of relapse and recidivism among its alums and cannot yet report those figures, he and his colleagues noted that, like any other type of treatment for a disease or condition, some people need a higher dosage than others.
"You often hear people saying, 'So-and-so is going back to rehab, rehab must not work,' but it's just that not everybody's the same," Weiss said. "Sometimes people get it the first time, sometimes people need more. A lot of what you see in public are the people who need more."