ssiw

Sun Is Addictive

img
  • - LYDIA OUCHENE
  • - M.D.C.M CANDIDATE
  • - MCGILL UNIVERSITY

STATISTICS ON MELANOMA IN CANADA

Sun exposure is recognized as one of the main risk factors for skin cancers. In fact, ultraviolet radiation (UVR) emitted by the sun can damage skin cells, causing them to transform and become cancerous. The skin possesses a natural defense against UVR: this s melanin, a molecule responsible for absorbing UVR. This molecule is pigmented, which is why we tan when we are exposed to sun for a prolonged time. In modern society, unfortunately, tanning has been associated with beauty, fitness and a healthy appearance, but this is wrong! In fact, a tanned skin reveals that a lot of melanin has been produced which reflects sun damage/damage of our cell DNA, and thus, a less healthy skin. For this reason, prolonged exposure to sunlight without skin protection as well as tanning must be avoided.

Despite knowing these risks, an increasing number of people seek to absolutely maintain their tan by using artificial tanning salons and outdoor unprotected sun exposure. In fact, growing use of sunbathing has been reported in North America in the past decades. Some people even resort to tanning oils and sunbathing

reflectors. Scientific studies have shown that “sun worshipers” may have symptoms of dependence to UV light similar to drugs, smoking and alcohol. In a study of 145 beachgoers in the United States, 53% of them had a tanning addiction. Examples of addiction symptoms include continuing to tan despite attempts to stop, persistent tanning even with harmful consequences such as developing skin cancer, and neglect of other responsibilities in order to keep a tan. More surprising is that some individuals continue to tan beyond what is necessary to reach their desired appearance.
img
img
img

“They found that when these individuals are exposed to UVR, their brain cells release a molecule, dopamine, associated with rewards, pleasure and arousal”

  • - DR. NETCHIPOROUK

WHAT EXPLAINS THESE ADDICTIVE BEHAVIORS?

A group of researchers in Texas questioned what happens in the brain of individuals that are addicted to indoor tanning. “They found that when these individuals are exposed to UVR, their brain cells release a molecule, dopamine, associated with rewards, pleasure and arousal”, says Dr. Netchiporouk an Assistant Professor of Dermatology at McGill University. Dopamine is also found increased in people with alcohol dependence, gambling and other substances addiction. The more this molecule increased, the more the tanners are dependent on tanning.

WHAT EXPLAINS THESE ADDICTIVE BEHAVIORS?

"When the skin is exposed to ultraviolet rays, from either sunlight or indoors tanning devices, as our DNA is damaged by UV rays, it triggers the skin cells release both melanin (i.e., pigment) and another molecule called β-endorphin which is related to pleasure, good mood and resistance to pain. “It is like an endogenous morphine. Repetitive exposition to UV light can lead to physical dependence" explains Dr. Netchiporouk.

According to Dr. Litvinov, a Director in Dermatology Research at McGill University, studies on mice are key to understand how this molecule mediates tanning addiction. A team of researchers from Harvard Medical School led by Dr. Fisher investigated what happens to mice that receive UV light compared to those who do not. "Not only did they find high level of β-endorphin in exposed mice, but when this molecule was artificially blocked, the mice showed signs of withdrawal. Moreover, the fact that these findings were not present in mice that did not receive sun rays, confirms that UV light triggers behavioral changes in these animals like in humans”, says Dr. Litvinov. “The researchers used a reliable trick looking at tail elevation in mice when they get morphine. Sun exposure and drugs like morphine trigger the same tail elevation response in mice. These studies really explain that sun can be addictive”, Dr. Litvinov.

img
A similar increase in β-endorphin release is found in humans exposed to UV light. It is demonstrated that sunlight leads to mood improvement in healthy adults. In a survey of 100 sunbed users, 69% responded that they were doing it “to feel good”. "Recent studies on humans demonstrate comparable findings to mice studies, regarding UVR-seeking behavior. Stopping sun exposure in frequent tanners induced withdrawal symptoms, which suggests an addiction. The increased levels of β-endorphin can explain this attitude" says Dr. Netchiporouk.
"The most predominant hypothesis is that this is a result of evolutionary adaptation to eliciting sun‐seeking behavior to prevent vitamin D deficiency leading to weak bones disease, called rickets", proposes Dr. Sassevile, Professor of Dermatology at McGill University. In fact, although chronic sun exposure has harmful health consequences, a small amount of sunlight is essential to obtain sufficient vitamin D to be in good health. Therefore, it is as if the body has created its own way of making sure we enjoy the sunlight, so that we can get adequate vitamin D . After all, our ancestors might have spent a significant amount of time hiding in a cave and were not all living near the equator, where the sun is abundant and strong. “Therefore, our body had to develop its own way to make sure people get some sun to generate necessary vitamin D ”, explains Dr. Sasseville. Of course, nowadays tanning is not necessary for obtaining enough vitamin D . An appropriate and safe level of sun exposure with sunscreen application as well as minimizing tan-seeking behavior is plentiful and recommended.
So far, there is little direct proof that this is true. Some studies suggest that low vitamin D is associated with sensitivity to pain in humans and to drug addiction in mice. Further research exploring the protective effects of universal vitamin D supplementation is needed. Until then, we recommend maintaining healthy vitamin D levels through use of inexpensive and safe oral supplements", recommends Dr. Netchiporouk.
  • Ouchene L, Muntyanu A, Netchiporouk E. Ultraviolet Radiation Seeking Behavior, Mediated by Endogenous β-Endorphin, Has Addictive Features. Journal of cutaneous medicine and surgery. 2020: 1203475420926990.
  • Harrington CR, Beswick TC, Leitenberger J, Minhajuddin A, Jacobe HT, Adinoff B. Addictive‐like behaviours to ultraviolet light among frequent indoor tanners. Clin Exp Dermatol: Clinical dermatology. 2011; 36(1):33-8.
  • Nguyen NT, Fisher DE. MITF and UV responses in skin: From pigmentation to addiction. Pigment cell & melanoma research. 2019; 32(2):224-36.
  • Miller KA, Piombo SE, Cho J, Higgins S, Wysong A, Sussman S, Cockburn MG, Leventhal AM. Prevalence of tanning addiction and behavioral health conditions among ethnically and racially diverse adolescents. J. Investig. Dermatol. 2018; 138(7):1511-7.
  • Fell, GL, Robinson, KC, Mao, J, Woolf, CJ, Fisher, DE. Skin β-endorphin mediates addiction to UV light. Cell. 2014; 157(7): 1527-1534
  • Toledo A, Karppinen T, Miettinen ME, Leppäluoto J, Vuolteenaho O, Ylianttila L, Kautiainen H, Snellman E, Partonen T. Narrow-band ultraviolet B (NB UV-B) exposures improve mood in healthy individuals differently depending on chronotype. Chronobiology international. 2019; 1-1.
  • Albers I, Zernickel E, Stern M, Broja M, Busch L, Heiss C, Grotheer V, Windolf J, Suschek CV. Blue light (λ=453 nm) nitric oxide dependently induces β-endorphin production of human skin keratinocytes in-vitro and increases systemic β-endorphin levels in humans in-vivo. Free Radic. Biol Med. 2019.
  • Kaur, M, Liguori, A, Lang, W, Rapp, SR, Fleischer Jr, AB, Feldman, SR. Induction of withdrawal-like symptoms in a small randomized, controlled trial of opioid blockade in frequent tanners. J. Am. Acad. Dermatol. 2006; 54(4): 709-711
  • Warthan, M. M., Uchida, T., & Wagner, R. F. (2005). UV light tanning as a type of substance-related disorder. Archives of Dermatology, 141(8), 963–966. https: //doi.org/10.1001/archderm.141.8.963
  • Trinko JR, Land BB, Solecki WB, Wickham RJ, Tellez LA, Maldonado-Aviles J, de Araujo IE, Addy NA, DiLeone RJ. vitamin D3: a role in dopamine circuit regulation, diet-induced obesity, and drug consumption. eNeuro. 2016; 3(3).
  • Fell GL, Robinson KC, Mao J, Woolf CJ, Fisher DE. Skin β-endorphin mediates addiction to UV light. Cell. 2014; 157(7):1527-1534. doi:10.1016/j.cell.2014.04.032