"We had previously shown that ultraviolet light has an effect on mood that tanners value," said Mandeep Kaur, M.D., lead author. "Now, in this small study, we've shown that some tanners actually experience withdrawal symptoms when the 'feel-good' chemicals are blocked."
The research – reported in the April issue of the Journal of the American Academy of Dermatology – involved eight frequent tanners and eight infrequent tanners. Frequent tanners were those who tan eight to 15 times a month, or more than necessary to maintain a tan. Infrequent tanners were those who use tanning beds no more than 12 times a year.
The research was designed to test the hypothesis that exposure to ultraviolet (UV) light may produce endorphins, brain chemicals that are linked to pain relief and euphoric feelings, and could play a role in tanning behavior. UV light occurs naturally in sunlight and is responsible for the tanning and burning effects of the sun. Artificial UV light is used in tanning beds and sunlamps.
In 2004, the Wake Forest researchers reported on a study in which participants had tanning sessions in two identical-looking tanning beds. Tanners spent half of each session in one bed, which used UV light, and half in the other, which didn't. Mood was measured before and after each tanning exposure. The results revealed greater relaxation and lower tension after UV exposure compared to non-UV exposure.
In the current study, the researchers hoped to discover whether endorphins could be driving the tanning behavior. Half of tanners were given an inactive drug and half were given a drug to block the effects endorphins and other opioids, which include narcotics such as morphine. Participants then tanned in both the UV and non-UV beds.
At higher doses of the opioid-blocking medication (15 mg. of naltrexone), frequent tanners showed a reduced preference for UV tanning. And, four of the eight frequent tanners 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 is may be driven in part by a mild dependence on opioids, most likely endorphins," said Steven Feldman, M.D., Ph.D., senior researcher and a professor of dermatology. "The nausea and jitteriness induced by the medication are consistent with symptoms of mild opiate withdrawal."
The researchers said that while the study is small, it supports the hypothesis that tanning behavior may be driven by endorphins in much the same way that the so-called "runner's high" helps to motivate runners.
Kaur said the finding is significant because, like other risky behaviors, it is important to understand why frequent tanners choose the activity. Exposure to UV through tanning has been shown to damage the genetic information in cells and is linked to the development of skin cancer. Despite this, there was a 300 percent increase in the number of indoor tanners in the United States between 1986 and 1996.
The research was funded, in part, by the National Institutes of Health.
Co-researchers were Anthony Liguori, Ph.D., Wei Lang, Ph.D., Stephen Rapp, Ph.D., and Alan Fleischer Jr., M.D., all with Wake Forest Baptist.
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About Wake Forest University Baptist Medical Center: Wake Forest Baptist is an academic health system comprised of North Carolina Baptist Hospital and Wake Forest University Health Sciences, which operates the university's School of Medicine. The system comprises 1,282 acute care, psychiatric, rehabilitation and long-term care beds and is consistently ranked as one of "America's Best Hospitals" by U.S. News & World Report.
Journal of the American Academy of Dermatology