People who cannot stop lounging in the sun or using sunbeds, even when they know the risks of skin cancer, may be suffering from tanning addiction.

Despite numerous campaigns to inform sunbathers of the dangers of skin cancer, the incidence of malignant melanoma, the most deadly type of skin cancer, is rising fast in Britain with 6,000 new cases diagnised each year.

Rates of skin cancer are rising rapidly among teenagers and young adults, with cases doubling in the past 20 years.Researchers from the University of Texas say they have found evidence that suggests sunbathing could be habit-forming.

Using criteria adapted from those used to screen people for alcoholism and drug dependency, the researchers interviewed 145 beach-goers about their sunbathing habits.

Using data from the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, they classed 53 per cent as dependent on ultraviolet light tanning.

Professor Richard Wagner, senior author of the study, said: "Dermatologists often talk about people who seem 'addicted to the sun' - people who know it's not good for them to be bronzed all the time, but don't seem to be able to stop tanning.

Professor Wagner said: "It's interesting that by slightly modifying tools used to identify substance-related disorders, we can actually see an objective similarity between regular tanning and those disorders."

"This is a new idea, and we didn't know how it would turn out, although there has been mixed evidence from other studies suggesting that tanning increases endorphin production, which could be addictive," he added.

"Certainly, this could explain why educational interventions haven't been more successful."

The research has been published online in Archives of Dermatology.