The New York Yankees are like a psychiatric patient, who, after years on the couch, finally reaches a period of blooming mental health, forified by the illusion that he understands himselt at last.

Point out the warts on the world champions' faces, as former teammate Sparky Lyle has done in an expose diary, and the Yanks say calmly, "That ol' Sparky sure has us pegged. Ain't we just a bunch of crazies?"

Not anymore. The Yankees are losing their gift for dementia. Only owner George Steinbrenner remains predictable.

"Sparky Lyle is the dumbest athlete I ever met," said Steinbrenner after learning that he shared the top rottenbanana billing with Reggie Jackson in Lyle's book "Bronx Zoo."

"He has prostituted himself to make a buck." For the most part, the Yank are the soul of moderation. In times of crisis, Manager Bob Lemon says, "I think I'll have another beer. Maybe the whole thing will go away."

Tommy John has brought his infectious bonhomie and Luis Tiamt his blithe sarcasm to the once bleak New York clubhouse. At last, the wits outnumber the nitwits.

Even Jackson has found his proper paradoxical role. Other Yankees watch him with bemusement as they would a gifted but insecure child who makes huge mudpies, then drops them on his head to attract attention.

The time may come when the therapeutic benefits of back-to-back World Series triumphs wear off and the Yanks suddenly find themselves old, cantankerous and left arrears.

Then, their encyclopedia knowledge of their faults may be corrosive. But, for the moment, the Yanks are imperturbable -- the first trauma-proof team.

Truth came Thursday evening. New York had lost its first seven exhibition games. What potential for fun.

Throughout the American League East, Red Sox, Orioles, Brewers and Tiger cocked their ears expecting volcanic rumblings. Would Steinbrenner give edicts? Waould Billy Martin suddenly materialize behind the bat rack?

"I couldn't care less," said Steinbrenner. "It means nothing. We won't have all our regulars in the lineup until the middle of next week.

"Even if we lost 17 in a row, the guys on this team would figure that meant we'd start the season by winning 17 in a row," said left fielder Roy White.

If the Bronx Bombers don't watch out, they will become as sane and dull as their drably brilliant forebearers.

Are the eccentric champs of the late 70s gradually turning into carbon copies of the old Yankees?

"Hrumph," said Baltimore Manager Earl Weaver, "it'd be just like the spoil-sport Yankees of the old days to have one seven-game losing streak all season and have it in spring training when the darn thing don't count against 'em."

Except for Steinbrenner the Yanks certainly absorbed Lyle's best body punches without a wince.

"Sparky Lyle is no longer welcome in Yankee Stadium," said Steinbrenner. "Once his playing days are over and that shouldn't be long, I'd like to see him try to get in our park again.

"I think we have a right to refuse to sell him a ticket.

"It's an outright lie that I fired an office girl over a tuna fish sandwich. I'm almost certain it was peanut butter and jelly."

Lyle's criticism has given Steinbrenner a perfect opportunity to saddle his white horse and come charging to the defense of the players.

"Just a few weeks ago Lyle was at a roast for Thurman Munson," said Steinbrenner, "and he was slapping everybody on the back. I asked him, 'If you like us so much, why did you write that book"'

"Sparky said, 'Aw, George, there's nothing new in that book, I just did it for the money.'"

How many authors can claim such critical accuracy in appraising their work?

Curiously, it may be the Yankees' new attitude of total equanimity, combined with their advancing age, that is their greatest potential enemy.

If any team ever had reason for overconfidence, this is the one.

"After what happened last year (coming from 14 games behind), it may be hard for us to get real excited if we fall behind by a few games in mid-season," said third baseman Craig Nettles.

Once the Yankees were Murderers Row, now they call themselves Millionaires Row -- pointing to the lockers of John, Tiant, Catfish Hunter and Don Gullett standing in a row. That, frighteningly, doesn't include Ron Guidry.

Chris Chambliss' thumb injury appears to be chronic -- a whole winter has not solved it. Lou Piniella, Roy White, Nettles, John and Tiant will average 36 years of age by pennantrace time. Munson's arm continues to plague him.

"Veteran players can be a doubleedged thing," said Weaver mischieviously. "if a guy like Chambliss slumps, you gotta stick with him all the way. But what if that's the year he goes over the hill and ends the whole darned season at.220? Then he can kill ya.

"The Yankees are far from invincible."

Maybe. But the Yankees have a weapon that is new in baseball: emotional armor. For two years they were called the psychodrama on wheels. Every day was a dugout orgy of what Mao's Red Brigade would have called "revolutionary self-criticism."

In the Yankees' case, the pinstriped comrades simply came to know and appreciate each other at greater depth and under greater pressure than almost any team before them.

Their utter confidence that they comprehended baseball's central mystery -- "how to win," reached such a point that they actually seemed serene and certain of themselves although they trailed Los Angeles, 2-games-to-o, in the World Series.

That sense of psychic well-being, of indesturctible belligerent poise, may set these Yankees apart from the rest of baseball far more than mere talent, or hard cash.