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Research Updates

Steven R. Feldman, MD, PhD

Is Tanning Addictive?

Steven R. Feldman, MD, PhD

Tuesday, October 03, 2006

Despite the adverse effects of ultraviolet (UV) exposure, the indoor tanning business is booming.1 It has been one of the fastest growing industries in the United States, with approximately 32 million tanners and estimated revenues of more than $1 billion/year in 1997, growing to $5 billion/year in 2002.2 Between 1986 and 1996, there was a three-fold increase in the percentage of Americans who used tanning booths.3 Women and young people (16-34 years old) are significantly more likely to use such devices and to use them regularly.4 Tanners vary widely in their use of tanning beds, but 10% or more have over 20 hours of exposure per year.4

Studies into the reasons behind excessive tanning have focused primarily on psychosocial factors such as appearance motivation, personal beliefs, and perceptions of risk. It seems self-evident that the main reason people tan is to have darker skin. Yet while some will tan a few times to get a tan, others tan far more often than needed to maintain one, to the point that it seems like an "addiction" for some frequent tanners.

To see if tanning does have addictive qualities, Wartham et al. gave 145 tanners a questionnaire testing DSM-IV-TR (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision) addiction criteria and a version of the CAGE (a brief alcoholism questionnaire) modified to evaluate tanning behavior.5 Seventy-seven tanners (53%) exhibited addictive behaviors based on DSM-IV-TR criteria, and 26 tanners (18%) exhibited addictive behaviors based on both DSM-IV-TR and CAGE criteria. These data suggest that frequent tanning has features similar to other addictive behaviors.

These findings were supported by more recent work by Zeller et al., who conducted telephone interviews with more than 1,000 adolescents.6 They identified "difficulty in quitting" indoor tanning in 267 adolescents (20.9% of total) who tanned indoors more than once in the previous year. Difficulty in quitting was more likely with younger age at initiation (age 13 years or younger vs. ages 16-17; odds ratio = 4.3, 95% confidence interval 1.3-14.7) and higher frequency of use (P=0.009), even after accounting for positive or negative consequences of indoor tanning and other demographics. Those with difficulty in quitting were more likely to report that tanning was relaxing. The investigators concluded that the findings were consistent with other potentially addictive behaviors taken up during adolescence.

Is tanning behavior simply an excessive behavior driven by social perceptions about tanning, or might there be a physiologic effect of UV exposure that drives tanning behavior? Reports that tanning is relaxing suggest that physical effects are possible. To explore this, our group performed a blinded, placebo-controlled trial of UV vs. non-UV stimuli in 14 frequent tanners.7 The frequent tanners were tanned in otherwise identical UV and non-UV tanning beds on Monday and Wednesday (so that if one bed tanned them, they wouldn't know which it was). On Friday, they were given a choice of beds. Almost invariably, they chose additional tanning from the UV bed.7 They reported that the UV bed was more relaxing than the non-UV bed.

It appears that UV does provide a physiologic stimulus that is perceived positively by frequent tanners. What could account for this? Some studies, though not all, suggest that UV induces production of cutaneous endorphins.8-12 Might UV-induced endorphins account for a physiologic drive toward UV exposure in frequent tanners?

To test this, our group repeated the UV/non-UV choice study in 3 subjects given the opioid blocker naltrexone.13 In one subject, the preference for UV was diminished. In the other 2 subjects, however, an unexpected event occurred: Subjects developed nausea and jitteriness. These are symptoms associated with withdrawal in chronic narcotic addicts given a narcotic blocker. Could frequent tanners be addicted to UV-induced opioids or were the observed symptoms simply a non-specific effect of naltrexone?

To explore this further, we performed a blinded, placebo-controlled, escalating-dose trial of naltrexone in 8 frequent tanners and 8 controls.14 For controls, we chose people who had tanned in the past but who were not regular tanners (we did not want to expose tanning-naïve individuals to indoor tanning). Subjects were first given 5 mg of naltrexone or placebo at the first two sessions, 15 mg of naltrexone or placebo at the second two sessions, and 25 mg of naltrexone or placebo at the third two sessions.

None of the infrequent tanners developed nausea or jitteriness with placebo or with naltrexone. None of the frequent tanners developed these symptoms with the placebo. Four of the 8 frequent tanners did develop symptoms at the 15 mg naltrexone dose; 2 of the 4 with symptoms had symptoms so severe as to require withdrawal from the study.

These controlled trials support a physiologic effect of UV driving tanning behavior in frequent tanners. The naltrexone studies suggest that, at some level, opioids are involved in this physiologic pathway. Is tanning addictive? It certainly appears to be so for a subset of frequent tanners. Dermatologists need to remind patients of the harmful effects of UV exposure.

References

  1. Robinson JK, Rigel DS, Amonette RA. Trends in sun exposure knowledge, attitudes, and behaviors: 1986 to 1996. J Am Acad Dermatol. 1997;37(2 Pt 1):179-86.
  2. 32 Million New Tanners: Imagine What That Could Do for Your Salon. Tanning Trends. 1997.
  3. The $1,000,000 Industry. Looking Fit. 1992.
  4. Rhainds M, De Guire L, Claveau J. A population-based survey on the use of artificial tanning devices in the Province of Quebec, Canada. J Am Acad Dermatol. 1999;40(4):572-6.
  5. Warthan MM, Uchida T, Wagner RF Jr. UV light tanning as a type of substance-related disorder. Arch Dermatol. 2005;141(8):963-6.
  6. Zeller S, Lazovich D, Forster J, et al. Do adolescent indoor tanners exhibit dependency? J Am Acad Dermatol. 2006;54(4):589-96.
  7. Feldman SR, Liguori A, Kucenic M, et al. Ultraviolet exposure is a reinforcing stimulus in frequent indoor tanners. J Am Acad Dermatol. 2004;51(1):45-51.
  8. Gambichler T, Bader A, Vojvodic M, et al. Plasma levels of opioid peptides after sunbed exposures. Br J Dermatol. 2002;147(6):1207-11.
  9. Wintzen M, Ostijn DM, Polderman MC, et al. Total body exposure to ultraviolet radiation does not influence plasma levels of immunoreactive beta-endorphin in man. Photodermatol Photoimmunol Photomed. 2001;17(6):256-60.
  10. Wintzen M, de Winter S, Out-Luiting JJ, van Duinen SG, Vermeer BJ. Presence of immunoreactive beta-endorphin in human skin. Exp Dermatol. 2001;10(5):305-11.
  11. Wintzen M, Yaar M, Burbach JP, et al. Proopiomelanocortin gene product regulation in keratinocytes. J Invest Dermatol. 1996;106(4):673-8.
  12. Kaur M, Liguori A, Fleischer AB Jr, et al. Plasma beta-endorphin levels in frequent and infrequent tanners before and after ultraviolet and non-ultraviolet stimuli. J Am Acad Dermatol. 2006;54(5):919-20.
  13. Kaur M, Liguori A, Fleischer AB Jr, et al. Side effects of naltrexone observed in frequent tanners: could frequent tanners have ultraviolet-induced high opioid levels? J Am Acad Dermatol. 2005;52(5):916.
  14. Kaur M, Liguori A, Lang W, et al. Induction of withdrawal-like symptoms in a small randomized, controlled trial of opioid blockade in frequent tanners. J Am Acad Dermatol. 2006;54(4):709-11.
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