Translator: Mirjana Čutura Reviewer: Rhonda Jacobs
I'd like to start off by telling you a story.
It's about a woman named Barbara.
Now, unfortunately for Barbara,
when she was young,
unhealthy habits were modeled at home.
And several of her close relatives
struggled with a very specific type of disorder.
As Barbara got older,
she realized that exposure to a certain type of substance
was highly rewarding for her,
and she began actively seeking it out
and consuming it without experiencing, really, any negative consequences.
Over time though,
Barbara began to experience the negative health effects
associated with taking this substance for a long period of time.
She had intense cravings.
She began to struggle with depression.
And even though she had tried to reduce her intake several times,
she had been unsuccessful each time.
Now, I'm sure you all have an idea of what it is that Barbara is struggling with,
and if you had guessed addiction, then you would be correct.
Barbara's not alone in this.
One in five Canadians will meet the criteria for substance use disorder
at some point in their lifetime.
I want you to think about this.
I want you to look to the two people on your right-hand side
and then the two people on your left-hand side.
Statistically speaking,
this means that one of you will meet the criteria for substance use disorder
at some point in your lifetime.
Four in 10 Canadians
will meet the criteria for addiction to tobacco products.
Two in 10 Canadians will meet the criteria for addiction to alcohol.
And six in 100, about six percent of the population,
will meet the criteria for addiction to cannabis and other illicit substances.
The social cost of this, according to a 2006 study,
was approximately 39.8 billion dollars each year.
This means that it costs just over 1,200 dollars
to every man, woman, and child in Canada.
And this includes both direct costs,
like the cost of healthcare and law enforcement,
and indirect costs, like lost productivity at work.
Now, Barbara's specific addiction
will cost Canadians approximately 4.5 billion dollars each year.
Now, some of you may have an idea of what the substance Barbara is addicted to is.
Some of you might be guessing "tobacco,"
some of you might be thinking "alcohol,"
some of you might be thinking something a little harder, like cocaine or heroin.
In actuality, Barbara isn't addicted to any of these substances.
Barbara is addicted to food.
Now, some of you might be surprised by that statement,
and some of you may disagree with that statement.
And in fact, the controversy surrounding food addiction
has been waging for the better part of the last 10 years on two fronts.
The first is what I like to call the social media war.
On one side, you have individuals that claim to suffer from food addiction
and provide anecdotal evidence of their own experiences
and the experiences of the people that they know.
And on the other side is -
you have individuals that claim that the words "food addiction"
are simply a cover, an excuse for developing obesity
or for having low self-control.
The other front on which this controversy is waged is in the scientific one.
Ten years ago,
health scientists started saying, "Look, we've got people coming to us,
and they are showing hallmark features of addiction:
They are showing tolerance.
They're showing withdrawal.
They're showing impulse-control issues."
And on the other side,
you had individuals that studied the sort of classic drugs of abuse,
like cocaine and like heroin,
who said that food could not be classified in the same way as those drugs
and that the neurobiological things that happen when someone becomes addicted
aren't present in individuals that claim to suffer from food addiction.
Now, this is where I came in.
This is when I began to be interested in research,
and I had been exposed to this controversy in social media,
and I'd been exposed to it in the scientific field,
and I was really interested.
So when I started my research, I started with a very simple question.
And that question was,
"Can the rewarding properties of food produce addiction?"
Now, one of the hallmark features of addiction is compulsion.
And if you look up the definition of "compulsion" in the dictionary,
it is "the irresistible urge
to behave in a way that runs contrary to your express, conscious wishes."
In addiction, we see this present as individuals
that are unable to stop themselves from consuming a substance
even if they no longer wish to
and even if they no longer derive any enjoyment from doing so.
So I went back to my original question,
"Can the rewarding properties of food produce addiction?"
and I modified it to,
"Can the rewarding properties of food produce compulsion,
this hallmark feature of addiction?"
Now, to do this, I used an already-established model,
and I exposed animals - rats, specifically - to a substance
that is commonly found in food and also happens to be highly rewarding.
And that substance is refined white sugar.
And I exposed these animals to a concentration
that is commonly found in sweetened beverages.
So I used a 10 percent concentration,
and for comparison,
the average can of pop has about 11 percent.
And I exposed these animals to this concentration of sugar
for 12 hours a day, every day for about a month.
And some very interesting things happened.
The first is that they began to binge.
They were consuming about five percent of their body weight
in the first hour every time they had access to the sugar.
Now, for comparison,
you can think of someone my size and my body weight
drinking about three liters of pop
or eating one-third of a kilo of sugar in one hour.
They also heavily escalated their intake over time.
By the end, in a 12-hour period,
they were consuming roughly one-fifth of their body weight,
which, again, for comparison,
is someone like me consuming 13 liters of pop
or 1.3 kilos of refined white sugar.
Imagine ...
drinking this
or eating this
every day.
So this is really shocking to me.
But what I was interested in
was whether exposure to this amount of sugar could produce compulsion.
Now, unfortunately, you can't ask an animal,
"Are you addicted to something?"
You can't ask an animal, "Are you compulsive?"
So I had to put them in an evolutionarily relevant situation,
one that pit their instinctual mechanism for avoiding danger
versus this learned behavior to seek out and consume sugar.
And when I did that,
the animals that had been consuming massive amounts of sugar
completely ignored -
they completely overrode this instinctual mechanism in favor of seeking out sugar.
And this is something that normal, healthy animals will not do.
But what was happening neurobiologically?
What was happening in their brains?
Well, there's some very specific changes that happen to a brain
when it becomes addicted to a substance,
and the changes that happen are different
depending on the type of the brain area that you're looking at.
The specific area that I was interested
is implicated in survival-based motivated behaviors.
And it happens to sit between two other brain areas
that have already been heavily implicated in the development of addiction.
The first in the amygdala, which processes emotional and rewarding information,
and the other is the striatum,
which is responsible for reinforcement-based learning
and motor control.
Now, this area had actually already been looked at by a colleague of mine,
and he was looking at it in animals that self-administered cocaine,
classic drug of abuse, over a long period of time.
And he was able to show that there's a very unique change
that happens to the neurons in this brain area.
They respond very differently to dopamine,
which is the brain's primary rewarding neurotransmitter,
than the neurons do in the brains of animals
that had either had no exposure to cocaine
or had been exposed to cocaine
but weren't self-administering it for a long period of time.
Now, when I looked at this brain area in my animals,
to my astonishment, I found exactly the same change in their brains
as what was happening in animals that were self-administering cocaine.
So, what's happening?
What does this mean?
Well, our brains are highly evolved, adapted organs.
And our brains have evolved to seek out rewarding substances
and perform rewarding behaviors
because in our evolutionary history, that meant survival:
things like having sex, eating good food, avoiding danger.
Unfortunately, this highly adapted system,
when it's exposed to unnaturally reinforcing substances like drugs -
this formerly adaptive process becomes maladaptive.
There's this war going on between our evolved biology,
that pushes us to consume rewarding substances
and pushes us to perform rewarding behaviors,
versus our modern environment,
a society in which unnaturally reinforcing substances are plentifully available.
This is why we are starting to see addictions to things
that are fundamentally new to our modern society:
addictions to things like gambling, to video games, and to food.
Now, there's still quite a bit of controversy
in the scientific literature
about what exactly the properties of food are
that can produce addiction.
But I think, in general, as a society,
we need to start thinking about addiction beyond drugs.
We need to stop having such a rigid idea
of what the substances are that can produce addiction.
We need to stop thinking about it as drugs versus other.
Because, really, any highly rewarding substance or behavior
can produce the same behavioral and neurological things
that we see in addiction.
We need to start thinking of addiction
as a very-old brain's way of trying to deal with a very new problem.
So I want you to do something for me when you leave here today.
I want you to just be aware.
And when you see hotly-debated topics like this one
in social media and other spheres,
I want you to think,
and I want you to question,
and I want you to investigate
because, as I found out,
addiction doesn't necessarily look like what it used to any more.
Thank you.
(Applause)