People who are hooked on indoor tanning may also be prone to substance abuse problems and to anxiety, a new study in the Archives of Dermatology finds.

The research doesn't conclude that those who love indoor tanning will become drug addicts, but it suggests that tanning addicts may have underlying mood disturbances that really should be treated by mental health professionals.

For the study, researchers interviewed 421 students from a large state university in the U.S. northeast. Among the students, 229 students reported they had tanned in indoor tanning salons. The students were then assessed for indoor tanning addiction, based on two tests used to judge other forms of addiction.

In general, tanning addicts were more likely to say they tanned frequently and that they had missed social or work activities so that they could go tan. Most also reported unsuccessful attempts to cut down on indoor-tanning time, or said they felt guilty about tanning too much.

A total of 90 (39.3 per cent) met criteria for tanning addiction on one addiction test, and 70 (30.6 percent) met criteria on the other test. Fifty of the study participants, just under 22 per cent, met the criteria for addiction on both of the two questionnaires.

The researchers then assessed the students for symptoms of anxiety and asked them about their use of alcohol, marijuana and other substances.

They found that those students who were classified as addicted to tanning were also more likely to have symptoms of anxiety and/or greater use of alcohol and drugs than their peers who were not addicted to indoor tanning.

The 50 participants who met the criteria for tanning addiction in both questionnaires had slightly higher levels of anxiety symptoms, as well as higher rates of alcohol and marijuana use.

"This study provides further support for the notion that tanning may be conceptualized as an addictive behavior for a subgroup of individuals who tan indoors," conclude study authors Catherine E. Mosher, PhD, of Memorial Sloan-Kettering Cancer Center in New York City and Sharon Danoff-Burg, PhD, of the University at Albany in New York.

This is not the first study to note that indoor tanning can become addictive for some. Some studies have suggested that ultraviolet light exposure from tanning beds and the sun promotes the release of endorphins, which are released by our brains' pleasure centres.

Tanning addicts typically report that UV light makes them feel more relaxed and less tense. They often continue to return to tanning, even though they know the practice is damaging their skin and could lead to skin cancer.

The researchers say their findings suggest that there may be a subgroup of individuals who can become addicted to indoor tanning. For these people, they say, it may be necessary to treat their "underlying mood disorder."

"Further research should evaluate the usefulness of incorporating a brief anxiety and depression screening for individuals who tan indoors," the researchers write.

"Patients with anxiety or depression could be referred to mental health professionals for diagnosis and treatment."