A lot of addiction actually ends by age 30 - something like 50 percent of all addictions with the exception of tobacco - and I think a lot of what's going on there is that the self-control areas of the brain are finally developed enough to be able to stop yourself from relapsing or just continuing. There is a maturational aspect to it as well.

I don't have kids, but I've often noticed when people first become parents they seem to completely forget their own adolescence and they start to, as their kids become teenagers, try to do the things that didn't stop them themselves. And I jokingly frame this as: Your brain gets wiped of those memories when you become a parent.

I know that sounds really extreme, but if you just look at the history, you will find Harry Anslinger [first U.S. commissioner of the Bureau of Narcotics] going on about satanic swing and how reefer will make black people think they're as good as white people - which to him, obviously, was a very horrible outcome. This is the basis of our drug laws.

Do we really want to base our 21st-century policy on what the colonialist preferred at a certain time in history, not at all based on health or what the preferences of different cultures might be? That's just ridiculous.

We absolutely should legalize marijuana.

A lot of the stuff that we say about drugs is just wrong.

Science could never get you to make alcohol and tobacco legal and marijuana illegal. Only racism can do that.