Before he became a renowned neuroscientist and drug abuse specialist, Dr. Carl Hart dabbled in selling and using drugs while growing up in Miami.

Hart said the overwhelming majority of drugs users don't have a drug problem, and he's advocating for governments to change their approach.

"The first thing I would do," said Hart, a medical doctor and associate professor of psychology at Columbia University, "I would make sure that we stop arresting people."

Drugs are often used as a scapegoat for other problems such as poverty and crime, said Hart, adding that drugs are not as addictive as we have been told.

Hart said the vast majority of people who use drugs like crack cocaine, heroin, and methamphetamine are not addicted and are able to go to work, pay taxes, bills, and take care of their families.

"When you have this relatively small percentage of users becoming addicted, it tells you that it's not the drug itself. The people who we see — for example on [East] Hastings — The reason why they are there, it varies. If we really want to know we'd have to give them individual assessments."

"You could disrupt drug taking behaviour if you had a careful understanding of what was motivating [it]," said Hart.

"Sometimes people have trauma or co-occurring psychiatric disorders that you have to treat. Other times they're just destitute."

Shift in public policy needed: Hart

Hart said public policy needs to shift focus toward treating people's real reasons for their drug addiction, and that may involve better mental health services or economic opportunities.

Instead of the U.S.'s war on drugs, Hart would rather see his country adopt drug policies similar to those in Portugal and the Czech Republic, where all drugs have been decriminalized, and arrests have been replaced with citations similar to traffic violations.

Hart also said we need to change the way we educate people about drugs.

"Stop exaggerating the harmful effects of drugs, and teach people how to be safe with drugs. Teach people how not to overindulge, just like we do with alcohol."

To hear the full interview with Dr. Carl Hart listen to the audio labelled Dr. Carl Hart