New findings on-line in the journal Addiction Biology may help explain why.
The research suggests indoor tanning taps into the brain's reward center.
Researchers measured blood flow during the tanning sessions of seven frequent tanners. They noted brain changes consistent with other things considered rewarding, such as money, food or drugs. They suspect UV radiation may play a role.
But a spokesman representing the indoor tanning industry says that just because some people over do things does not mean they are addicted.