The city that never sleeps may also be the one that never smiles. A new study says that New York City is the unhappiest major city in America, after you adjust for income.

The study was done by the University of British Columbia's Vancouver School of Economics and professor Joshua Gottlieb. The study examined the data from the 2010 U.S. Centers for Disease Control survey on American life satisfaction.

The researchers found a link between people's unhappiness and a city's economic decline. In New York City, research has shown that neighborhoods are becoming more defined by income levels. And the fact that rent has increased by 75 percent since 2000, though income fell by five percent, could have contributed to the unhappiness levels of NYC.

As that abstract for the "Unhappy Cities" paper states, "Individuals willingly endure less happiness in exchange for higher incomes or lower housing costs."

The paper notes that new residents of a city are just as unhappy as people with roots in that city, which once more indicates that work and economic reasons seem to be more important than happiness.

Gottlieb told "New York Magazine" that there was some evidence that cities with milder winters have residents with greater satisfaction. The climate of New York and the overall weather can affect people's sense of well-being.

But New York is a city of workers and hustlers, and for many, jobs are more important than happiness.

"People have many goals in life beyond pure happiness. Parents choose to have children, even though that lowers measured happiness. They may move to a less happy city because it provides a more fulfilling job, or has other attributes that enrich their lives in other ways," Gottlieb told New York Magazine. "It suggests that people have deeper preferences than hedonic pleasure, and can consciously make complicated tradeoffs."

The "Unhappy Cities" paper (PDF) goes beyond New York City and lists the top ten unhappy major cities in the U.S. based up on the research:

1. New York, NY
2. Pittsburgh, PA
3. Louisville, KY
4. Milwaukee, WI
5. Detroit, MI
6. Indianapolis, IN
7. St. Louis, MO
8. Las Vegas, NV
9. Buffalo, NY
10. Philadelphia, PA

The original 2010 survey by the Centers for Disease Control was answered by 300,000 subjects nationwide.

Gottlieb's study is a working paper that has not yet been peer-reviewed.

Photo: Andree Kroger