Do some people get addicted more easily?

Molly Crockett - I'm not an expert on this, but I do believe that there's some evidence that the structure of your dopamine system in the brain can make you susceptible to different kinds of addictions. This work was done actually by Barry Everitt at Cambridge and Trevor Robbins and that group. They found that, for example, a certain type of dopamine receptor in the striatum, the density of that receptor can make rats more or less susceptible to addictions, but I'm not sure the extent to which we know this in humans.

Ginny - I think there was also some work that suggested that rats that were more impulsive were also more likely to become addicted. So, they had a little test where when a light flashes on, the rat has to poke its nose in the box that has the light in order to get a reward. Rats who were likely to poke their noses in boxes before the lights came on, so were impulsive, seem to be more likely to become addicted when they were given drugs. Again, I don't know if that applies to humans yet or if it's just in the rat models.

Molly Crockett - I think yeah, absolutely, that work also has been done in Cambridge and I think it has been extended to humans that you can see in addicts that measures of impulsivity similar to the tests with the nose poke and the lights. People who are addicted to various substances are more impulsive on those kinds of tests certainly.