Our ability to study the brain has been limited because of our tools and our tools have only allowed us to look at one neurotransmitter and we haven't looked so much into co-localization and co-release of transmitters. Our thinking is hampered by our tools.

If you're a member of a despised group, look out! They'll find a drug and associate you with its use. There are a lot of people in the gay community using methamphetamine and paying taxes and going to work and doing well.

When you have the national narrative being "crack is awful and black people are using it," why go against that narrative when you want to get that publication in The New York Times or wherever? It encourages people to play right into it.

I am glad that people are trying to have a rational conversation about drugs.

Much of the early work focused on dopamine and we were really looking for rewarding sorts of effects and sure enough, we only found that. But you can destroy the main dopamine-producing structures of the brain and you can still get an animal to self-administer drugs like cocaine.

The policy that received more attention particularly in the past decade and a half or so has been the US cocaine policy, the differential treatment of crack versus powder cocaine and question is how my research impacted my view on policy. Clearly that policy is not based on the weight of the scientific evidence. That is when the policy was implemented, the concern about crack cocaine was so great that something had to be done and congress acted in the only way they knew how, they passed policy and that's what a responsible society should do.

The way we're currently educating people about heroin is to say that heroin is so awful. Heroin is not so much the problem. It's when you combine it. It's hard to die from heroin alone.