So it could certainly be helpful to learn how the feeling of UV light on the skin produces pleasure. The new research may help elucidate that: it shows, for example, that UV light is essential to sunning pleasure, since UV-filtered light did not produce the same brain responses.
However, simply demonstrating that a person’s reward areas light up doesn’t show that she’s an addict. For one thing, most people find food, sex and alcohol fun — and their brains’ pleasure regions light up as evidence — but they never become addicted to any of those things. Enjoyment doesn’t equal addiction.
Incidentally, neither does craving — by itself. A person’s brain may show a response indicating desire, but that doesn’t mean that urge is uncontrollable or that the person’s ability to make choices is impaired.
Addiction is much more complicated. We do a disservice both to the understanding of the brain and to our decisions regarding drug treatment and policy when we think about it so simplistically.
Neither pleasure nor desire is sufficient to define addiction, and brain scans typically don’t offer more information than that. Until we look what leads a small proportion of people — who tend to be unhappy, stressed, mentally ill or unemployed — to persist in unhealthy behavior despite negative consequences, or, in other words, addiction, we won’t make real progress.
Tanning may become an addiction for some people — but research like this can’t prove it.