Most Replayed Moment: The Role of Dopamine in Addiction and Motivation - Anna Lembke

Transcript from https://podmenti.com/t/31ffaa66ac122341

Uh
You wrote one of the most iconic well known books about
Dopamine which
propelled the subject matter of dopamine into the public consciousness.
But I guess the most important question I should ask you is
Why does dopamine matter?
Uh.
Good question. Good good place to start.
I mean dopamine matters because it's
Fundamental to our survival.
Right. So it's the chemical that we make in our brain that tells us this is something we should approach, explore, investigate.
So it's it's really almost the survival chemical.
So what is dopamine, if you had to explain it to a ten year old.
How would you go about explaining it?
So dopamine is a chemical that we make in our brain.
Um
Yeah.
Has
many different functions, but one of its most important functions is that it helps us experience pleasure, reward.
And motivation.
Um, it may be even more important for the motivation to do things than it is for the pleasure itself. So, for example, there's a very famous experiment.
in which rats were engineered to have no dopamine in the brain's reward pathway.
And the scientists discovered that if they put food in the rat's mouth, the rat would eat the food, would seem to get some pleasure from the food, if you can determine that from watching a rat eat, which I think they felt like they could.
Uh, but if you put the food even a body length away, the rat will starve to death.
The idea being that without dopamine
We're not motivated to seek out the things that we need for our basic survival.
That's crazy. Mm-hmm. So you get a rat, you put
The food an inch from its
Mouth
And it will starve to death because it doesn't have dopamine. The dopamine required to just
Reach out and eat. Yeah, essentially. Maybe it's not an inch, maybe it's a little more than an inch. But the idea being that
Dopamine is necessary.
to be motivated to do the work to get the thing that we need.
And
Having an understanding of dopamine.
How might that improve my life?
Having a basic understanding of
how dopamine works, how we process pleasure and pain.
And also
what happens with dopamine as we go from
Adaptive recreational use to maladaptive addictive use.
is something that is really useful, especially for those of us living in the modern world.
Where now we're exposed to so many reinforcing substances and behaviors that
we've all become vulnerable to the problem of addiction.
And one of the
biggest misconceptions of on the subject of dopamine because it's kind of thrown around in society. I see it in my group chats, people saying I need more dopamine or whatever, or
You know, that person just craves dopamine. What
What are the biggest misconceptions you've come across?
the main misconception is that somehow we can get addicted to dopamine. We're not getting addicted to dopamine itself. Dopamine is neither good nor bad. It's a signal
To tell us.
Верна
Something that we're doing is potentially useful for our survival.
And also it's related to
what we predicted about how rewarding or pleasurable something would be.
And so it's really
Um you know, I sort of sometimes I joke it's like the um
Reward theory of relativity?
Dopamine is in the sense that pleasure and pain really are truly relative to one another. And so dopamine gives us information about where we are in that relativity scale between pleasure and pain. And when you say relative, you mean I mean
It's quite fitting for anyone that can't see we have a s uh set of scales on the table.
And scales are relative to each other because if you pour in one end, the other end goes
Up and if you pour in the other end, the other end goes up and this end goes down. And when you s say relative, that's what you're describing, right? Yes, that's what that's what I'm describing. Yes. Okay. And
What activities that I do every day
Have an impact on my dopamine.
Well probably
almost everything, you know, in some ways. Um I mean every time we are doing something that's pleasurable, reinforcing, rewarding
That will affect dopamine. It's it's really the primary signal.
That lets us know that this thing is potentially important for our survival, as I mentioned.
Um but you know even
Um aversive stimuli can
Yeah, trigger dopamine. Oh, something that's painful or not pleasurable. Dopamine gets involved in in that um equation.
Anything that's novel or new
is something that triggers our uh dopamine in in our reward pathway.
Dopamine is fundamental for movement, so
Not just pleasure and reward, but also movement.
So for example, Parkinson's disease, which is a disease related to stiffness and tremor.
Is caused by a depletion of dopamine in a part of the brain called the substantia nigra. And as dopamine gets depleted in that part of the brain, people lose the ability to move their bodies.
And it's probably no coincidence that the same neurotransmitter that is so important for pleasure, reward, motivation is also really important for movement because
Most organisms have to locomote toward the object of their desire.
We want that thing, we have to exert effort, right? We have to put in the work to go get it.
But in the world today we really
Don't have to do that, right? We can swipe right, we can swipe left, and all of a sudden it magically appears at the touch of a finger.
And that's very confusing for our brains because that's not how we evolved. We really evolved for ha for having to do
Quite a bit of upfront work.
For a tiny little bit of reward.
I just wanna
Before we move on, talk about this point you said, because I think it's quite foundational to everything we're gonna talk about, about dopamine being relative to pain. Mm-hmm.
And I have this set of scales in front of me. And here I have some
chemicals that are
likely to produce dopamine in my brain, I believe. Right. Alcohol. I have some rum. I have some whiskey. I have some vodka. Mm-hmm.
And can you explain to me using this rum whiskey in vodka?
how dopamine is relative to pain and what's going on in my brain.
Sure.
So
One of the most exciting findings in neuroscience in the past seventy five years is that pleasure and pain are co-located in the brain.
So the same parts of the brain that process pleasure also process pain.
And in a very simple reductionist kind of way, they work like opposite sides of a balance.
So imagine that deep in your brain's reward pathway, which is
Another exciting discovery, right? That there's this dedicated reward pathway of the brain that consists broadly speaking of the prefrontal cortex, which is this large gray matter area right behind our foreheads that's so important for future planning.
for delayed gratification for appreciating future consequences.
You might think of it as like the brakes on the car if we're going to s analogize to to a to an engine.
And then deep, you know, in the brain we've got
what we call the limbic areas or the emotion brain.
And there you have the nucleus accumbens and the ventral tegmental area that are rich in dopamine releasing neurons, right? And they act like the accelerator on the car.
So when you've got a healthy functioning brain, you've got
Enough accelerator, but not too much, right? So enough dopamine being released, but not too much. And you've got a healthy prefrontal cortex.
Putting the breaks
on that dopamine release.
When people
Um become addicted.
There's either a problem with the brakes, the prefrontal cortex, or
Or the accelerator, the nucleus accumbens and ventral tegmental area.
Or both, right? What we're finding w is that there's actually a disconnect. So there are large neuronal circuits and pathways between those deep limbic structures and the prefrontal cortex that literally get severed or disconnected when people become addicted.
As we think about
Pleasure and pain being co located in the same parts of the brain, working like opposite sides of the balance.
In order to understand what happens in the addicted brain is to appreciate that there are
Fundamental rules governing this balance. And one of the most important rules is the is that the balance wants to remain level. It does not want to be tilted very long to the side of either pleasure or
or pain.
And in fact, what our brain does is first tilt an equal and opposite amount to whatever the initial stimulus is. So I'm gonna try to illustrate that here. So let's say our
Initial stimulus is alcohol. Now alcohol works through its own chemical pathway. It works on our endogenous opioid system, the opioids that we make. We have receptors for opioids in our brains. It works on our endogenous GABA system, which is our calming neurotransmitter.
And at the end of the day, it releases dopamine in the reward pathway.
So any potentially addictive substance will release dopamine in the reward pathway the more that's released and the faster that's released the
in a given individual.
the more likely that substance is to be addictive.
Now
Another important concept here is what we call drug of choice, which is to say what relo r releases a lot of
dopamine in your brain may not release a lot of dopamine in my brain and vice versa, right? Which is
This idea that people have predilections to different kinds of drugs. And by the way, people can get addicted to behaviors too.
I should emphasize that.
When you say drug of choice.
You mean the brain has a particular
Sensitivity to that.
drug in terms of dopamine.
Yes. Okay. The more dopamine that's released, the faster that it's released, the more likely that drug is to be addictive for a given individual. So you're holding some whiskey there. I'm holding some whiskey. There could be a brain that is very sensitive to whiskey.
And there could be a different brain that you could pull all the whiskey in you like and the dopamine response is
Sort of limited.
Exactly. Okay. And for many of my patients who
become addicted to alcohol, they will tell you that from the first moment they had alcohol.
They knew they were either in trouble or had met their best friend or some combination. It was a very potent experience for them.
All right. So let's let's go ahead and put this on the pleasure side of the balance.
Dopamine's being released, but no sooner has that happened than my brain
will work very hard to restore a level balance. And by the way, a level balance is what neuroscientists call
Homeostasis.
Okay. And one of the overarching physiologic drives for all living organisms is to return to homeostasis. Homeostasis is that parameter of
what's often called called affordances or states of being that are adaptive and healthy for the organism. For example, like we have a certain
Homostasis of body temperature. And if we go much
too much beyond that, either too high or too low, we will disintegrate and die, right? So homeostasis is that that
States of being that are compatible with existence and and potentially advantageous too. Sort of baseline level That's right. Okay. Yeah, baseline level. And by the way, we're always releasing dopamine at a kind of tonic baseline level in our brains. I sometimes think of it as the heartbeat of the brain.
So what's happened here for people that can't see is you put a little bit of whiskey into one end of the scale.
The pleasure side of the scale, and the other side of the scale has risen, because now there's whiskey with um in the the pleasure side, which I guess has released dopamine.
Exactly. So now we've released dopamine in the reward pathway. Okay. Because the pain side went up, does that mean there's now less pain in the brain?
Well, I think, you know, again, this is a metaphor. It's an oversimplification. The idea here is just when we press on the pleasure side, we're releasing dopamine in the reward pathway and experiencing pl
Okay.
But no sooner has that happened than our brain will
try to compensate or adapt.
To increase dopamine firing.
By downregulating dopamine transmission, for example, by involuting postsynaptic dopamine receptors.
So our brain is a bunch of wires, you know, um, that conduct these electrical signals and and these long spindly cells are called neurons.
And the thing about neurons is that they don't actually touch end to end. There's a little gap or space between them, and that gap is called the synapse.
And that
gap or synapse is bridged by what we call neurotransmitters, and dopamine is one of those neurotransmitters. Okay.
And when the presynaptic neuron pulses and releases dopamine, it crosses the synapse and
and binds to a receptor on the post synaptic neuron.
Which either continues or aborts that electrical signal. Does that make sense? Yes. Okay. So one of the ways that our brain can decrease the effects of dopamine, decreased dopamine transmission, is by involuting or taking inside the neuron the postsynaptic receptor.
That way when dopamine is released it has nowhere to bind. Oh okay. So it's like removing the docking station.
Exactly. Very good. It's removing the documentation. So essentially getting back to our scale, we've we've, you know, ingested alcohol, we've increased dopamine firing in the reward pathway, but remember our pleasure pain balance wants to return to if they level position, level with the ground.
Homeostasis. So it's going to decrease dopamine transmission by, for example, involuting those postsynaptic dopamine receptors.
But one thing about the brain in its process of trying to get back to homeostasis is
And again, I like to think of this neuroadaptation process as these gremlins hopping on the pain side of the balance to bring it level again. You don't have gremlins here, you have these little rocks. But let's go ahead and put a rock on the pain side of the balance and the and the this these rocks are are friends.
Right, their job is to level the balance. Cause remember we got to go back to homeostasis. So I'm gonna put a rock on and you're gonna say, Oh my gosh, it overshot.
Right. It now I've got
It pressed down on the the pain side of the mouth. But that's exactly what happens in our brains. In this process of neuroadaptation.
Those gremlins hopping on the pain side of the balance are
don't get off as soon as the balance is level. They stay on until we're tilted.
An equal and opposite amount.
So is that what a hangover is or
A come down as
They would say in when people take drugs, they say I um I have a come down.
Exactly. That's exactly what it is. That's the hangover, the come down, the blue Monday.
Or on a much smaller scale just that moment of craving.
Right? That moment of wanting to have one more shot.
Right. Why does it overshoot? Why can't it just perfectly hit homeostasis?
Such a great question.
'Cause then we'd feel fine. Yeah. Why did Mother Nature do that to us? So cruel, right? Yeah.
Okay.
I'm gonna tell you an evolutionary just so story. What we mean by that is we don't really know why, you know, this mechanism exists, but from an evolutionary perspective.
If you're living in a world of scarcity and ever present danger.
This is the perfect mechanism.
To make sure that we're never satisfied with what we have, that we're always wanting more.
It's made us the ultimate seekers.
Okay, because
Immediately after getting something, I'm now
Feeling a lack of pleasure.
And I'm at a deficit or you know on the
the pain side of the scale, which means that I'm gonna go seeking out more dopamine.
And in a world where everything is quite scarce.
That could mean going on another four hour hunt the next day to go kill a gazelle or something.
Perfect. You got yeah, you got it perfectly. Okay, interesting. Yeah.
Okay, so that's gonna motivate me because
So but

Jesus, people that have hangovers don't seem very motivated. Right. So now that's it. So w why is that, right? It's because
Alcohol
Is a product of human engineering.
That releases so much dopamine all at once in the reward pathway that our brains are reeling to compensate.
Right. We we really weren't evolved.
For this much pleasure.
with this much easy access. As you said yourself, we were
really evolved for to have to do quite a lot of work up front.
And to be hungry and to be lonely and to be tired and then get a little bit of reward that would then bring us back up to
homeostasis. So really we were evolved to be pressing on the pain side of the balance in our effort to find pleasure. And then when we find it,
That little bit of food or clothing or shelter or a mate would bring us back to the level position. Does that make sense? Yeah, so you're you're telling me essentially that we're all wired.
To be
Addicted.
Because if this is how our brain works in a world
It's designed to seek out
more dopamine. But the problem we have now is we have all this synthetic dopamine effectively, like this sort of s synthetic chemicals and some synthetic things and you know, an internet that
Is wiring us to give us a
So much dopamine so easily.
Th that means that our brains are effectively like
mismatched to the world that we live in and therefore why to be addicted. Yeah, I think you actually said that. I I found a quote you said
In an interview where you said
We're all wired to be addicted, and if you're not addicted yet, it's right around the corner.
Right. Coming to a website near you. Yes. I w I guess I would
I would qualify that a little bit b by saying we're wired for survival.
In a world of scarcity.
That's not the world we live in now. We live in a world of overwhelming overabundance.
And so there is a mismatch between this ancient wiring that has us relentlessly pursuing pleasure in order to survive.
And a world that's so infused with pleasure and so many rewarding stimuli that now we're overwhelming our reward system, and our brains are reeling in response to try to compensate.
So what happens to this scale then in such a world where I can get a big hit of dopamine
all the time using some of these synthetic things or the internet or pornography or whatever else. What's going on with this scale over and over again?
Okay, great. So l let me get there. Let me first say though that
Remember
After we do something that's
highly pleasurable. Our brain compensates
with neuroadaptation, tilting an equal and opposite amount to the side of pain.
And then
restoring our balance back to the level position, right? Or what we call homeostasis. So this doesn't last forever, right? It's to pleasure
Then it's to pain, then it's back to the level position.
But if we continue to consume our drug of choice over days to weeks to months to years.
And we add in a whole bunch of other
Drugs and now we're consuming you know, pornography and smoking pot and eating
Um, donuts and you know, you name it.
All at the same time.
Then essentially what happens is
Those gremlins on the pain side of the balance.
end up camped out there.
For anyone that can't see, she put all of the rocks into the pain side to represent all of the addictive behaviors that this individual has now.
Taken on.
Right. And now
We've entered addicted brain.
By which I mean that we've changed our hedonic or joy set point.
To the side of pain.
Now we need more and more of our drug in more potent forms.
Not to get high and feel good, but just
to level the balance and feel normal. And this is not going to be enough.
To level the balance, I would have to like
Keep filling this.
Much more than this container can hold. And that would be in pursuit really of just
trying to level that balance so that we can feel normal and when we're not using
We're walking around with a balance.
Tilted toward the side of pain, experiencing the universal symptoms of withdrawal from any addictive substance or behavior.
Which are anxiety
Irritability, insomnia, depression.
And craving.
So if I manage to get enough vodka whiskey rum and pour it into the pleasure side of the scale, now that all the rocks are in the pain side of the scale, I manage to outweigh it.
It would it would
What would then happen? More rocks.
More rotten. Yes, more rough. So momentarily. Yeah.
I would maybe be a in a little bit of pleasure. Yes.
But then my brain would remove those docking stations again, remove more of them, and more rocks would go in and I'd slam down
on the pain side again, which means I need more alcohol.
To try and get up to pleasure and slant okay. So really you want to
You wanna
Like dopamine fast, or you need y you need to just
balance this. And this is so difficult because of the world we live in. It's almost it's it's it's funny enough,'cause this little scales experiment, um
analogy here is giving me a huge amount of empathy for people that are addicts. Oh gosh, I'm so glad you said that because
I think that is the key to empathy for the disease of addiction, as well as for people with the disease, having empathy for themselves is recognizing that on some level
Yeah.
it's it's out of their control, right? Because when we are tilted to the side of pain
The
Overwhelming drive to restore a level balance or restore homeostasis as quickly as possible.
overwhelms any other rational thought the consequences of my drug use, right? It's just like get back to the level position because if I do that, I'll at least feel temporarily better.
What you just listened to was a most replayed moment from a previous episode. If you want to listen to that full episode, I've linked it down below. Check the description. Thank you.