Marijuana is not not harmful, but is the least harmful psychoactive substance that we have, with the possible exception of caffeine.

Addiction is when you fall in love with a drug instead of a child or a lover and the learning that takes part in that part of the brain is designed by evolution to get us to persist despite negative consequences to do what we need to do - because I don't know anybody who could survive a relationship or parenting if not for the ability to persist despite negative consequences. The problem is when that gets misdirected to a drug and then you can find yourself in some very negative and potentially deadly situations.

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.

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.

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

In order for people to recover, we can't just say 'love is all we need.'

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