People who use tanning beds frequently might get more than just darker skin and a higher risk of cancer.

A new study suggests they can become addicted, too.

"We had previously shown that ultraviolet light has an effect on mood that tanners value," said Mandeep Kaur of the Wake Forest University Baptist Medical Center. "Now, in this small study, we've shown that some tanners actually experience withdrawal symptoms when the 'feel-good' chemicals are blocked."

Not conclusive

The study involved only 16 people, too small to be considered conclusive. Half of them tanned eight to 15 times a month, which the researchers say is more than necessary to maintain a tan. The other half tanned no more than 12 times a year.

Researchers gave some of the subjects a drug that blocks the effects of pleasure-inducing endorphins and other opioids that are naturally released by the brain and which have been associated with the UV light of a tanning bed.

At higher doses of the blocking medication, frequent tanners were less inclined to tan, and half of them reported nausea or jitteriness. None of the infrequent tanners who took the drug reported these symptoms.

"The finding was unexpected and is consistent with the hypothesis that frequent tanning may be driven in part by a mild dependence on opioids, most likely endorphins," said Steven Feldman, a professor of dermatology at the university. "The nausea and jitteriness induced by the medication are consistent with symptoms of mild opiate withdrawal."

The research is detailed in the April issue of the Journal of the American Academy of Dermatology.

Previous research by the same team found that subjects using UV tanning beds were more relaxed afterward than people who used beds that did not have UV light.

Big business

Tanning beds are a $2 billion-a-year industry in the United States, according to the Skin Cancer Foundation. The tanning salon industry claims the UV light is harmless and even healthy. One claim from proponents is that tanning prevents sunburn, thereby reducing the chance of skin cancer.

But UV tanning, from the sun or in a bed, damages genetic information in cells and is linked to the development of skin cancer, say the Wake Forest researchers.

The Skin Cancer Foundation agrees with that view. The darkening of skin is a direct result of damaged cells.

According to the foundation: "By increasing exposure to carcinogenic UV rays, the risk of skin cancer is increased."

Some studies of indoor tanning and cancer have proved inconclusive, while others have suggested a link. Of particular note, the Skin Cancer Foundation points out: "No study has ever suggested a protective role for indoor tanning."

The U.S. Food and Drug Administration takes this stance: "UV radiation from the sun, tanning beds, or from sun lamps may cause skin cancer. While skin cancer has been associated with sunburn, moderate tanning may also produce the same effect."

And what about that vitamin D we're supposed to produce with the help of sunlight?

From the FDA: "It doesn't take much sunlight to make all the vitamin D you can use — certainly far less than it takes to get a suntan."

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