A Columbia professor is challenging everything we thought we knew about drug addiction.
Dr. Carl Hart said that "there's no biological distinction" between addictive and non-addictive drugs in a Wednesday interview with MSNBC's Chris Hayes. According to Hart, there is no distinction between humans' biological desire for drugs like marijuana and cocaine.
"All of the drugs that we're talking about come from plant-based products so these things were in our environment, were here before us, in many cases," Hart said. "So it's not a surprise that we have these chemicals in our brains as well. At some doses these things are used to protect you, used to help you feel better, and at other doses they're used to be toxic, they can kill you."
Hart said that humans' addiction to drugs stems not from their makeup, but from social context. He suggested the environment in which people consume and obtain cocaine encourages a competitive and addictive habit, while the environment in which people obtain and consume marijuana -- which is more widely accessible -- does not.
"So you're saying there's nothing chemically in the distinction between these two drugs or what they are doing to your brain that produces addiction or not, saying whether it produces addiction or not is the social context or degree of restraint around access to it?" asked Hayes.
"That plays a large part in why these drugs are addictive or not," Hart responded.
The professor added that preexisting psychiatric disorders may amplify an individual's perceived addiction to a drug.
Watch the segment above.