This year marks the 90th anniversary of a signal moment in advertising history: the first time a problem was turned into a social stigma so a company could sell a product to fix it.

In 1922, Gerard Lambert was in his office at the family's pharmaceutical company in St. Louis. One of his employees read him an article in a British medical journal that used the word halitosis to describe bad breath.

Lambert's father had helped invent a product called Listerine, which dentists used as an antiseptic and which Lambert Pharmaceutical Co. marketed for a whole range of uses, from treating gonorrhea to cleaning floors. Lambert started an advertising company that turned halitosis into a national epidemic for which Listerine was the cure. Today, mouthwash is a $689 million-a-year business.

Lambert's legacy is all around us. Got weeds in your lawn? Oily hair? A dirty car? Buy the product; erase the shame. It was genius.

When you combine Lambert's legacy with the awesome power of the drug industry to create demand, $689 million a year is nothing.

There is a commercial for a prescription medication called Nuvigil, targeted at people with "shift-work disorder," a condition I was unaware of.

I understand that people who work overnight shifts can have trouble adjusting. People who work rotating shifts have particular trouble. What I didn't understand was that this was a "disorder" — a medically recognized condition having to do with interrupted "circadian rhythms."

Some people deal with this better than others; a couple cups of coffee and they're good to go. Others — and here's where the pharmaceutical industry comes in — need more help.

When you have a "disorder," insurers sometimes pay for treatment. This is important when you're trying to sell a drug for $18 a tablet.

In 1998, a company called Cephalon began marketing Provigil, the trade name for a drug called modafinil. It is a stimulant that keeps you awake as amphetamines do, without the frantic behavior and with far less potential for addiction and abuse.

At first, it was marketed for narcolepsy, a fairly rare sleep disorder. Then medical science decided that excessive sleepiness at work could be classified as a condition called "shift-work disorder." It was like Lambert's discovery that bad breath was a medical condition.

A new market opened up for Provigil. Long-haul truckers and students figured out some off-label uses for it, as did the U.S. military.

Provigil was very profitable for Cephalon, and one reason the Israeli pharmaceutical firm Teva bought the firm for $6.8 billion last year. But, sadly, all drugs eventually go off patent, and the exclusive rights to produce modafinil expired this year.

Cephalon fought hard, buying out generic manufacturing rights for a while, but now customers can get it for as little as $1.20 a tablet. And the price will go nowhere but down.

Hence the radio commercials for Nuvigil. Rather than lose its cash cow, Cephalon created Nuvigil, which it says is a better, longer-lasting drug for excessive sleepiness because of shift-work disorder. Whether Nuvigil is an entirely new drug is a matter of some dispute. More important for Cephalon, however, is that Nuvigil has patent protection for 11 more years.

Nuvigil, and, for that matter, Provigil, can keep you awake for two or three days under the right conditions. But out on the frontiers of science, they're thinking that staying awake for a week or more might be possible.

The federal government's Defense Advanced Research Projects Agency knows there might be times when it would be useful for soldiers and pilots to stay awake and alert for long stretches. DARPA dreams of the day when a soldier can take a hit from a squeeze bottle of nasal spray containing Orexin-A, a synthesized version of a natural hormone that can keep you going for eight hours at a time.

Sleep-replacement drugs surely will be abused, and nobody's quite sure what the long-term effects might be. It's the kind of question that keeps you up at night.