How do addictions start?

Neuroscientist Camilla Nord filled us in on this tricky question...

Camilla - So I think of the start of addictions as needing, sort of, three ingredients. You need vulnerabilities in trait, vulnerabilities in your current state, and then exposure to the addictive substance. So those are kind of the three factors. What I mean by trait is something genetic or, earlier in your life, environmental, that has predisposed you to either try, and then if you try then become dependent on, a particular substance. So there's a fair amount of research on certain genetic polymorphisms that make you more or less susceptible to, say, alcohol dependence. Sometimes this is a general susceptibility, like it would apply to any kind of substance, but sometimes it's very specific.

There's a mutation in the mu-opioid receptor that makes you more susceptible to opioid addictions, at least in one paper. So that's the kind of stuff you can't really control, your background. Then there's also vulnerabilities in your current state. So people are much more likely to develop addictions when they're in a stressed or distressed state. People are more likely to try, and then to also become dependent on, different substances in those kinds of states. And then the third thing is trying a substance that can become addictive, and that is a little bit independent. So most people who've used drugs recreationally don't become dependent. So the two are not totally interlinked and they seem to be conferred by different types of risk. You might have a risk to try a drug, both state and trait, but you might not have the risk to become dependent on that particular drug.