Sunshine as addictive as heroin?
If the many media reports are to be believed: "Sunshine can be addictive like heroin." The claim comes via a study published in Cell based on an experiment carried out on mice at Harvard Medical School. Researchers found that ultraviolet light exposure leads to elevated endorphin levels - the body's own 'feel good' internal morphine - that mice experience withdrawal effects after exposure and that chronic ultraviolet light exposure causes dependency and 'addiction-like' behaviour.
Although the study was carried out on animals, the authors speculated that their findings may help to explain why we love lying in the sun and that in addition to topping up our tans, sunbathing may be the most natural way to satisfy our cravings for a 'sunshine fix' in the same way that drug addicts yearn for their drug of choice.
Reading the findings of this study took me back to 1998, when I appeared as a 'behavioural addiction expert' on a daytime BBC television show alongside people who said they were addicted to tanning (dubbed by the researchers on the programme as 'tanorexia'). I have to admit that none of the case studies on the show appeared to be addicted to tanning - at least based on my six behavioural addiction criteria: salience (being the most important and preoccupying activity in the person's life), mood modifying, tolerance, withdrawal, conflict and relapse. But it did at least alert me to the fact that some people thought sunbathing and tanning were addictive.
On the show, people likened their excessive tanning to nicotine addiction, and there certainly appeared to be some similarities between the people interviewed and nicotine addiction, in the sense that the 'tanorexics' knew they were significantly increasing their chances of getting skin cancer as a direct result of their risky behaviour but felt they were unable to stop doing it, which you could argue is very similar to smoking despite knowing the health warnings.
Since then, tanorexia has become a topic for scientific investigation. A 2005 study published in the Archives of Dermatology claimed that a quarter of the sample of 145 'sun worshippers' would qualify as having a substance-related disorder if ultraviolet light was classed as the substance they craved. The paper also reported that frequent tanners experienced a "loss of control" over their tanning schedule and displayed a pattern of addiction similar to smokers and alcoholics.
A 2006 study, published in the Journal of the American Academy of Dermatology, reported that frequent tanners (those who tanned eight to 15 times a month) who took naltrexone, an endorphin blocker normally used to treat drug addictions, significantly reduced the amount of time spent tanning compared with a control group of light tanners.
Two years later, a study published in the American Journal of Health Behaviour reported that 27 per cent of 400 surveyed students were classified as "tanning dependent." The authors claimed that those classed as being tanning dependent had a number of similarities to substance users, including a higher prevalence among youths; an initial perception that the behaviour was image-enhancing; high health risks and disregard for warnings about those risks; and the activity being mood-enhancing.
A just-published study in the American Journal of Health Promotion surveyed 306 female students and classed 25 per cent of the respondents as "tanning dependent" based upon a self-devised tanning-dependence questionnaire.
But the problem with this and most of the psychological research on tanorexia is that almost all of it is carried out on relatively small convenience samples using self-reporting and non-psychometrically validated 'tanning addiction' measurement scales.
Although some studies suggest that some of my addiction criteria appear to have been met, I have yet to be convinced that any of the published studies show that all of them have been met. In short, empirical research evidence demonstrating a genuine addiction to tanning that encompasses all the known and expected physical and psychological consequences of addiction has yet to be proven.
- Griffiths is the director of the International Gaming Research Unit and Professor of Gambling Studies at Nottingham Trent University.
- This article was originally published on The Conversation.
- The Washington Post