Addiction To Tanning – Part 2 of 3
The two groups differed in variants of a gene called PTCHD2. No one knows unequivocally what that gene’s job is, but it does appear to act mainly in the brain. Some other gene variants known to be linked to addictive behavior were not clearly connected to tanning dependence. But Cartmel said that might be because the investigation group was too small to detect statistically strong differences. Dr David Fisher, chair of dermatology service at Massachusetts General Hospital in Boston, agreed that larger studies are needed.
So “There very well may be other genes associated with tanning dependence,” said Fisher, who was not elaborate in the research. Understanding the biology behind tanning dependence is important because the likely consequences – skin cancer – can be “devastating”. In a recent study, Fisher found that exposing mice to a daily dose of UV light boosted the animals’ blood levels of beta-endorphins – “feel-good” hormones that act out on the same brain pathways as opiate drugs, like heroin and morphine.
That suggests UV exposure is rewarding to the brain. One theory, according to Fisher, is that because sunlight triggers the husk to synthesize vitamin D, the human brain evolved to find UV exposure rewarding. But how do people know when they cross the line into “dependence?” Cartmel acknowledged that the concept of tanning dependence is still debated, and there is no authentic definition. People in the study were considered tanning-dependent if they were “positive” on three different questionnaires.