They've been coming in the mail for weeks. The news releases from various and sundry mental-health experts had all been bearing dire warnings about the side effects of the holidays. Beware the Christmas Blues. New Year's Eve may make you anxious and depressed. They read like labels on a gift box from Ralph Nader: The Surgeon General Has Determined that December is Dangerous to Your Health.

One news release carried a checklist of likely sources of anxiety. Another offered 10 ways to avoid severe depression. A third reminded me that if I do get depressed, I shouldn't feel depressed about it because it is normal for this time of year. A fourth warned that if I do get through the holidays feeling jolly, I'd better watch out, because I am probably heading straight for the post-holiday doldrums.

Now I happen to remember the good old days when the only people issuing warning about the holidays were the fire department and consumer product safety commissions, and I find this all a bit much. The mental experts have moved into the holiday business with all the muscle of the oil companies moving into Alaska.

But Mental Health is the growth industry of the '70s. If the experts approach December with the marketing enthusiams, of say, Polaroid, I suppose it's understandable. They are as invested in New Year's Eve as that small province in France known as Champagne.

I am not, I assure you, being cynical. I don't think the holiday blues are a myth. Some of my best friends are depressed. But I look at the mental-health industry from time to time with the jaundiced eye of an economist.

Mental Health is another major internaitional conglomerate, with a vast research division and an eye on the market. Like any other industry with payrolls to meet and a new crop of workers being funneled out of the universities, it is ever-expanding, seeking out new areas of need. The one thing that is essential for an expanding mental-health industry is an expanding category of "mental illness."

You don't have to be very ill to need "help" these days. It is now virtually un-American to have a marriage without a family counselor, and a divorce without a therapist to call you own. People in general are no longer rotten; they are temporarily "unhealthy." The worst epithet thrown at a partner in the midst of a flight these days isn't "You miserable s.o.b.!" but, rather, "You're sick, you're really sick!"

For the past several years, the industry has made strong inroads into what we used to call normal stress. Anxiety, a good solid conflict, a touch of ambivalence and the holiday blues have been gradually elevated or deparessed (forgive the expression) to the status of Serious Emotional Problems.

Last year it was the Life Ciris. Afer a book, "Passage," identified the disease, an entire subdivision of mental-health workers rose to cure it. Lord knows how many people who were still on their One True Course were helped into the Switch Forties.

This year, it seems that the most successful new line is self-help. Where but in American would people be so easily convinced that they needed expert help to get self-help?

Of course, like any other industry, the expert business has a certain built-in obsolescence. At the very least, they keep revising their old theories so that they'll have something new to offer. One generation of experts tells people precisely how to raise their children so that the next generation will teach them how to relax. That sort of thing.

The experts insist through all of this that they are only in business to help us "deal with the issues." In that pursuit, they keep identifying new issues for us to deal with. That's growth for you. That's expansion. That's the American Way.

The latest of these issues - temporarily pushing aside self-help - is, of course, December. The Holidays.

Of course, what we probably need to "deal with" is the issue of experts in our lives and our growing dependency on them. But I hesitate to suggest it. It sound suspiciously like another growth opportunity for the industry: How to Get The Expert Out of Your Life. I can see itnow, just as soon as they're through with their post-holiday depression.