Dopamine Baseline, Impulsivity & Addiction | Dr. Anna Lempke & Dr.Andrew Huberman

00:00:00.400 | I and many listeners of this podcast are obsessed with dopamine and what is dopamine? How does it

00:00:10.840 | work? We all hear that dopamine is this molecule associated with pleasure. I think the term

00:00:17.200 | dopamine hits, like I'm getting a dopamine hit from this, from Instagram or from likes or from

00:00:22.740 | praise or from whatever is now commonly heard. What is dopamine and what are maybe some things

00:00:32.380 | about dopamine that most people don't know and probably that I don't know either?

00:00:36.700 | So dopamine is a neurotransmitter and neurotransmitters are those molecules that

00:00:42.320 | bridge the gap between two neurons. So they essentially allow one neuron, the presynaptic

00:00:48.580 | neuron to communicate with the postsynaptic neuron. Dopamine is intimately associated with

00:00:56.260 | the experience of reward, but also with movement, which I think is really interesting because

00:01:01.320 | movement and reward are linked, right? If you think about, you know, early humans, you had

00:01:07.980 | to move in order to go seek out the water or the meat or whatever it was. And even in the

00:01:15.360 | most primitive organisms, dopamine is released when food is sensed in the environment. For

00:01:20.400 | example, C. elegans, a very primitive worm. So dopamine is this really powerful, important

00:01:30.460 | molecule in the brain that helps us experience pleasure. It's not the only neurotransmitter involved

00:01:38.380 | in pleasure, but it's a really, really important one. And if you want to think about something that

00:01:44.240 | most people don't know about dopamine, which I think is really interesting is that we are always

00:01:49.000 | releasing dopamine at a kind of tonic baseline rate. And it's really the deviation from that baseline

00:01:56.580 | rather than like hits of dopamine in a vacuum that make a difference. So when we experience pleasure,

00:02:02.440 | our dopamine release goes above baseline. And likewise, dopamine can go below that tonic baseline.

00:02:09.400 | And then we experience a kind of pain. Interesting. So is it fair to say that one's baseline levels of

00:02:17.140 | dopamine, how frequently we are releasing dopamine in the absence of some, I don't know, drug or food or

00:02:24.420 | experience just sitting, being, is that associated with how happy somebody is, their kind of baseline of

00:02:31.860 | happiness or level of depression? There is evidence that shows that people who are depressed may indeed

00:02:39.600 | have lower tonic levels of dopamine. So that's a really reasonable thought. And there's some evidence

00:02:48.000 | to suggest that that may be true. The other thing that we know, and this is, you know, really kind of

00:02:54.680 | what, what the book is about, is that if we expose ourselves chronically to substances or behaviors that

00:03:04.240 | repeatedly release large amounts of dopamine in our brain's reward pathway, that we can change our tonic

00:03:12.260 | baseline and actually lower it over time as our brain tries to compensate for all of that dopamine,

00:03:18.840 | which is more really than we were designed to, to experience.

00:03:23.880 | Interesting. And is it would, is it, um, the case that our baseline levels of dopamine are set by our genetics,

00:03:30.180 | by our heredity?

00:03:31.120 | Well, I think, you know, if you think about sort of, you know, the early stages of development in infancy,

00:03:37.060 | certainly that is true. You're kind of, you know, born with probably whatever is your baseline level,

00:03:42.900 | but obviously your experiences can have a huge impact on where your, your dopamine level ultimately settles

00:03:51.780 | out. So, um, if somebody's disposition is one of, um, constant excitement and anticipation or easily excited,

00:04:00.180 | these are, I think about the kind of people where you say, "Hey, do you want to check out this new place for tacos?"

00:04:04.760 | and they're like, "Yeah, that'd be great." And other people are, um, a little more cynical, harder to budge,

00:04:10.200 | like my bulldog Costello, um, very, very stable, low levels of dopamine with big inflections in his case.

00:04:17.400 | Um, is that, do you think that's a set in terms of, um, our parents and obviously nature and nurture interact,

00:04:27.480 | but is that, is dopamine at the core of our temperament?

00:04:30.920 | I don't really think we know the answer to that, but I will say that people are definitely born

00:04:39.480 | with different temperaments and those temperaments do affect their ability to experience joy. Um,

00:04:48.280 | and, and, you know, we've known that for a long time and we described that in many different ways.

00:04:52.920 | One of the ways that we describe that in the modern era is to use psychiatric nomenclature,

00:04:57.800 | like this person has a dysthymic temperament, or, you know, this person has chronic major depressive

00:05:03.320 | disorder. Um, in terms of looking specifically at who's vulnerable to addiction, um, that's an

00:05:10.520 | interesting sort of mixed bag because when you look at, uh, the research on risk factors for

00:05:16.280 | addiction, so what kind of temperament, uh, of a person makes them more vulnerable to addiction,

00:05:21.240 | you see, um, some interesting findings. First, you see that people who are more impulsive

00:05:26.520 | are more vulnerable to addiction. So what is impulsivity? That means having difficulty, um,

00:05:31.720 | putting space between the thought or desire to do something and actually doing it. And people who have

00:05:38.040 | difficulty putting a space there who are, who have a thought to do something and just do it

00:05:42.600 | impulsively are people who are more vulnerable to addiction.

00:05:46.520 | Interesting. Could I, uh, in terms of impulsivity, is this something that relates literally to,

00:05:52.280 | um, the startle reflex? Like I, for instance, as a, uh, lab director, I'm familiar with walking around

00:05:57.320 | my lab. And, um, when I decide deciding I'm going to talk to my people, of course, when they knock on my

00:06:01.800 | door, it's always like, wait, why am I being bothered right now? Even though I love to talk to them,

00:06:05.560 | but I walk around my lab from time to time and some people I notice I'll say, um,

00:06:09.320 | do you have a moment? And they'll slowly turn around and say, yeah, or no, in some cases.

00:06:15.240 | Um, and other people will jump the moment I say their name, they actually have a,

00:06:20.200 | uh, a kind of a heightened, um, startle reflex. Right.

00:06:23.320 | Is that related to impulsivity or is what you're referring to, um, an attempt to, uh,

00:06:29.080 | withhold behavior that's very deliberate under very deliberate conditions?

00:06:32.920 | Yeah. So I don't think that that startle reflex is, is necessarily related to impulsivity. That,

00:06:38.120 | that can be related to anxiety. So people who are high anxiety, people will tend to have more

00:06:43.240 | of a startle reflex. Impulsivity is a little bit different. And by the way, impulsivity is not always

00:06:49.000 | bad, right? Um, impulsivity is, is that thing where there's not a lot of self editing or worrying about

00:06:58.600 | future consequences. You know, you have the idea to do something and you do it. And of course we can

00:07:04.760 | imagine many scenarios where that's absolutely wonderful. Um, you know, there can be a sort of,

00:07:11.080 | uh, let's say intimate, um, interactions between people where you wouldn't really want to be super

00:07:18.520 | inhibited about it. Right. You would want to be disinhibited and, and impulsive. Um, there, I can also

00:07:23.880 | like imagine like sort of, um, fight or flight scenarios, like battle scenarios, right. Where, where it would

00:07:30.440 | really be good to be impulsive and just go, rah, you know, just where hesitation can cost you your life.

00:07:35.720 | Yes, that's right. That's right. But you know, and I think this brings up a really,

00:07:40.120 | something that I've come to believe after 25 years of practicing psychiatry is that what we now

00:07:48.840 | conceptualize in our current ecosystem as mental illness are actually traits that in another ecosystem

00:07:59.160 | might be very advantageous. They're just not advantageous right now because of the world that

00:08:05.240 | we live in. And, and I think, you know, impulsivity is potentially one of those, right.

00:08:10.760 | Cause we live in this world that's sort of like, you have to, um, constantly be thinking

00:08:16.760 | sort of rationally about the consequences of X, Y, or Z. And it's such a sensory rich environment,

00:08:24.440 | right. That we're being bombarded with all of these opportunities, these sensory opportunities,

00:08:30.280 | and we have to constantly check ourselves. And so, so, so impulsivity is something that

00:08:34.840 | right now, um, can be a difficult trait, but isn't in and of itself a bad thing.

00:08:41.080 | I see. Yeah.

00:08:41.880 | Yeah. And it's, I, I'm beginning to realize it's a fine line between spontaneity and impulsivity.

00:08:46.360 | Yeah.

Dopamine Baseline, Impulsivity & Addiction | Dr. Anna Lempke & Dr.Andrew Huberman

Chapters