Okay, should we address him as Dr. Tom Cruise from now on? Or will the Rev. Dr. Cruise suffice?

Whatever: Anybody who watched the actor's performance on NBC's "Today" show yesterday witnessed an unsettling transformation. The movie star, who has long embraced Scientology, launched a full-bore assault on the psychiatric profession, sticking to a script that his church (founded, mind you, by a hack science fiction writer) has been promoting for decades.

"Psychiatry is a pseudoscience," he told host Matt Lauer, later saying: "You don't know the history of psychiatry. I do."

Cruise looked like a man possessed -- or at least in need of an Ativan -- leaning insistently forward in his chair, hammering Lauer when the host suggested that some people were actually, you know, helped when doctors prescribed psychiatric drugs. Lauer sparred with Cruise specifically over whether it made sense for Brooke Shields to have sought therapy and taken antidepressants for postpartum depression -- a decision that Cruise had previously criticized.

Forget medical research: "There is no such thing as a chemical imbalance in a body," said Cruise, who prescribed vitamins and exercise for depression. "The thing that I'm saying about Brooke is that there's misinformation, okay? And she doesn't understand the history of psychiatry. She -- she doesn't understand, in the same way that you don't understand it, Matt."

This is the second time in recent weeks that Cruise has made an issue of the mental state of Shields, who previously termed "irresponsible and dangerous" his comments about her medical treatment for depression.

On "Today," Cruise also raged against Adderall and Ritalin, often prescribed to treat hyperactivity and attention-deficit disorder in children. "Do you know what Adderall is? Do you know Ritalin? Do you know now that Ritalin is a street drug? Do you understand that?"

And the meltdown continued: "Matt, Matt, Matt, Matt, Matt, Matt, you don't even -- you're glib. You don't even know what Ritalin is," Cruise said. "If you start talking about chemical imbalance, you have to evaluate and read the research papers on how they came up with these theories, Matt, okay? That's what I've done."

Lauer called Cruise's command of the subject "impressive," but noted, "I'm not prescribing Ritalin, Tom. . . . I'm simply saying I know some people who have been helped by it."

At one point, Lauer seemed fed up: "You're telling me that your experiences with the people I know, which are zero, are more important than my experiences. . . . And I'm telling you, I've lived with these people and they're better."

Cruise then accused Lauer of "advocating" Ritalin.

"I am not," Lauer said.

The interview (which Lauer told viewers would continue on Monday -- oh, goody) is pegged to Cruise's role in the film "War of the Worlds," which opens Wednesday. But every interview with Cruise lately has seemed to revolve around the twin suns of Scientology and Katie Holmes, his new fiancee and a recent initiate to the church. His now-legendary professions of love on "Oprah" started what has become a series of manic moments in public, in which the screen idol appears to be losing his chiseled, steely reserve.

While Cruise Chernobyled on "Today," Holmes gazed at him adoringly from the wings of the set, where the interview was taped on Thursday.

Will any of this hurt Cruise's career?

"Don't immediately assume that he is ruining himself," said Allan Mayer, managing director of Los Angeles-based Sitrick and Co., which regularly handles celebrities' PR crises. "He himself has said he doesn't care, and who are we to say he's made a mistake? . . . What's the point of being a hugely successful and powerful movie star if you can't talk about the things that matter to you? We may think it's silly and bizarre, but it's obviously important to him."

As a top-level celebrity believer in Scientology, Cruise has been steeped in the lingo and policies of the late church founder, L. Ron Hubbard. (Hearing Cruise use a term like "ideal scene" during his exchange with Lauer would perk up the ears of anyone who's been in Scientology's orbit before.)

Hubbard launched his self-help movement in the 1950s with a book called "Dianetics: The Modern Science of Mental Health," and from early on, he battled with psychologists and psychiatrists. Indeed, Hubbard once wrote in an internal policy statement: "Our war has been forced to become to take over absolutely the field of mental healing on this planet in all forms."

Peg Nichols, a spokeswoman for the Landover-based Children and Adults With Attention-Deficit/Hyperactivity Disorder, said her office was flooded with calls yesterday about Cruise's statements. The group avoids comment on Scientology, but she advised people to be "smart consumers of medicine." And she asked: "Since when would a celebrity have expertise in medicine? Would you go to your doctor and ask him about movie roles?"

Special correspondent Korin Miller contributed to this report.

Matt, Matt, Matt, Matt, Matt, Matt: Tom Cruise tells "Today" show host Matt Lauer how much he doesn't know about Adderall and Ritalin.

He's in LOOOVE! On "Oprah," Tom Cruise

was giddy over Katie Holmes.