For decades, doctors, scientists, celebrities, and cool-cat executives were all used in cigarette ads to deflect fears that smoking was dangerous. The health-claim strategy evolved into “low-tar” claims that became the subject of a Supreme Court case in October 2008. We pulled these examples from a large documentation project by the Stanford University School of Medicine; many are on display at a branch of the New York Public Library through December 2008. Watch the slideshow.

On the day the Dow plunged almost 800 points, Erick Giliberti was doubling down on his smoking habit.

Before the turmoil, says Giliberti, a manager at Deloitte who works with mortgage-backed securities, “I was maybe a pack a week.” Now? “Probably double that…I can’t stare at my computer screen anymore and watch the market collapse in front of me—I just want to get away from it.”

Giliberti was standing outside the Deloitte offices at the World Financial Center in Lower Manhattan, furiously thumbing his BlackBerry with one hand and holding a Marlboro Light with the other. He is, he says, “32 going on 55.”

From the Financial Center to Wall Street itself to the shell-shocked (former) Lehman Brothers building in midtown Manhattan, it’s easy to find stressed-out financial workers sucking on cigarettes, and most will tell you they’re lighting up more often. Nobody is thinking of quitting.

A Lehman Brothers employee who, for now, has kept his job with new owner Barclays, is smoking “20, 30% more,” in part because “we don’t really have much work to do these days, so we just sit around and talk to people.”

Nearby, a woman named Liz, who has been let go from Lehman along with her boss, says that stress at the company in the past six months led her to start smoking for the first time in her life—at the age of 61.

“Everybody could tell that Lehman was falling apart the end of last year,” she says. “I was under a tremendous amount of pressure, so I picked up a cigarette.” It didn’t help matters that she lived with her daughter and her daughter’s fiancé, both of whom smoke.

Smoking and stress go hand in hand, but the relationship isn’t as simple as it appears, according to Matthew Palmatier, PhD, an assistant professor of psychology at Kansas State University, who is conducting research funded by the National Institutes of Health on the “reinforcing” and mood-regulating effects of nicotine on rats.

Smokers exhibit elevated physical signs of stress, Palmatier says. Further, smoking elevates those signs of stress. Yet smokers report stress reduction from their habit. “So it makes these stressed people physiologically even more stressed, but what they report is that it reduces their stress,” Palmatier says. One likely explanation is nicotine’s ability to stimulate the pleasure centers in the brain even as it stresses other systems.

A few blocks away, on Sixth Avenue, the 45-year-old De La Concha cigar shop remains one of the few businesses or offices in New York City where smoking is still legal. Tom Johansmeyer, a freelance PR rep for the shop, says De La Concha has become a socializing and networking spot for laid-off finance workers. Mind you, customers are switching from $10 or $15 cigars to the $8 house blend, the Grand Reserve.

One such customer is Tom Kochilas of Queens, N.Y., who was laid off in March from Merrill Lynch. He says he drops by the store daily for an $8 smoke.

Does the cigar help relieve the stress of being out of work? “I was actually more stressed when I was working,” he says. “Now I’m not stressed at all.” He puffs thoughtfully on his Grand Reserve. “Maybe that’s a bad thing.”