Are drugs really frying your brain? | Dr. Carl Hart

• So I started studying drugs because I got hoodwinked like everybody else. I thought that drugs were the source of the problems that we were seeing in our community.

• "All of us agree that the gravest domestic threat facing our nation today is drugs."

• But it turns out, I was wrong. Sometimes people ask, "When was the precise moment when you had this epiphany that, 'Oh, it's not the neurobiology of somebody, but instead it's the social context under which they operate?'" There wasn't a magical moment. There was a gradual change over many years of studying.

I learned that the vast majority of people who use drugs like crack cocaine or heroin did not become addicted. And these people behaved in ways that were so responsible, in ways so inconsistent based on anecdote, based on media reports. So this dissident caused me to start to shift my thinking. And then gradually over time, I realized much of what I had been told about drugs is pure nonsense.

Between 1990 and 2000, that is deemed the 'Decade of the Brain.' There was a lot of money into studying brain illnesses, brain disease. There was a lot of money in terms of learning about the brain.

And during that time, we are looking for some neural footprint of addiction. And we thought that once cocaine interacted with these dopamine neurons, it just had this almost magical power over the person's behavior. We've learned that that's not necessarily the case. In fact, it's a lot more complicated than that, and it has a lot more to do with the psychosocial environment under which the individual is operating - like lack of opportunity, lack of education, lack of healthcare.

All of these issues are with us today, as they were in the 1980s and 1990s when I thought that drugs were the source of the problem. Turns out not only was I wrong, society was wrong.

One of the ways that we studied the brain of drug users is through neuroimaging techniques: so, we bring people into a laboratory and then we take pictures of their brains. And if they are, for example, drug addicts, we would put them in one category and then we would compare their brains to people who've never used a drug.

And your pictures, you can say, "Well, if you look in this area of someone who uses drugs, you can see that it's not lighting up quite as much as the same area in someone who doesn't use a drug." And so therefore, that's evidence of neuropathology, neuro-damage.

It's a wild oversimplification because all you're doing is taking a snapshot of somebody's brain in one moment in time. And secondly, what we are seeing is people's brain structures being within the normal range of human variability. We have now mischaracterized people as being brain-damaged - and that's wrong.

So when we think of drug addiction, it's important for the lay audience to keep the focus on the person's behavior, and not on the person's brain. The person's behavior will tell you everything you need to know.

Are they not showing up for work? Are they not meeting their obligations at home? Are they not meeting their obligations in school? Has the person had multiple unsuccessful attempts at cutting down or scaling back or quitting their drug use?

All of these sort of signs are important indicators of whether someone is drug addicted or not. And notice, I didn't look at anyone's brain, I'm really looking at the person's behavior...