Carl Hart, a neuroscientist and professor at Columbia University, has given a powerful TED talk arguing for the decriminalisation of all drugs, challenging classist and racist stereotypes about drug use and calling for a new approach to the consumption of psychoactive substances.

Hart stresses that drug users must not be demonised and all lumped into the same category with a couple of powerful examples:

- "I grew up in the hood in Miami in a poor neighborhood. I came from a community in which drug use was prevalent. I kept a gun in my car. I engaged in petty crime. I used and sold drugs. But I stand before you today also -- emphasis on also -- a professor at Columbia University who studies drug addiction."

- "80 to 90 percent of people who use illegal drugs are not addicts. They don't have a drug problem. Most are responsible members of our society. They are employed. They pay their taxes. They take care of their families. And in some cases they even become president of the United States."

That would be the same President of the United States who recently said we must "follow the science, not the ideology" with regards to drug legislation.

Hart's talk runs 19 minutes but is well worth the watch, seeing him put forward models for treating low-level drug offenses like traffic fines and highlighting the self-perpetuating downward spiral of incarceration that comes with a punitive approach to drug use.

A few more key quotes:

- "People will always use drugs. They always have used drugs. We must learn to live with this fact."

- "What I know is that the drugs themselves are not the problem."

- "Each year we arrest 1.5 million people in this country for drug law violations, and 80% of those are for simple drug possession. Decriminalisation of possession would have a huge impact."

- "I believe we should decriminalise all drugs."