Welcome to Huberman Lab Essentials,

where we revisit past episodes for the

most potent and actionable science-based

tools for mental health, physical

health, and performance.

I'm Andrew Huberman, and I'm a professor

of neurobiology and opthalmology at

Stamford School of Medicine. Today we

are discussing aggression. I'm going to

explain to you that there are several

different types of aggression. For

instance, reactive aggression versus

proactive aggression. Meaning sometimes

people will be aggressive because they

feel threatened or they are protecting

those that they love who also feel

threatened. There's also proactive

aggression where people go out of their

way to deliberately try and harm others.

And there is indirect aggression which

is aggression not involving physical

violence. For instance, shaming people

and things of that sort. It turns out

that there are different biological

mechanisms underlying each of the

different types of aggression. And today

I will define those for you. I'll talk

about the neural circuits in the brain

and body that mediate each of the

different kinds of aggression. Talk

about some of the hormones and peptides

and neurotransmitters involved. I

promise to make it all accessible to

you. Even if you do not have any biology

or science background, I'm certain that

by the end of the episode, you will come

away with a much more thorough

understanding of what this thing that we

call aggression really is. And when you

see it in other people, I think it will

make more sense to you. And when you

observe it in yourself or the impulse to

engage in aggression, verbal or physical

or otherwise, I hope that you'll

understand it better as well. And of

course, the tools that I will describe

should allow you to modulate and control

aggressive tendencies or predispositions

to aggressiveness and just generally be

able to engage with people in a more

adaptive way. Overall, the context of

aggression really matters. So there are

instances where aggression is adaptive.

For instance, a mother protecting her

children. Of course, other forms of

aggression like unprovoked proactive

aggression, somebody simply being

violent to somebody else even when

unprovoked. Most of us cringe when we

see that kind of behavior. It can even

evoke aggression in people when they

observe that kind of behavior. Many of

you have probably heard the statement

that I believe arises from pop

psychology, not from formal academic

psychology, that aggression is just

sadness. It's a form of sadness that's

amplified and it shows up as aggression.

But when we look at the underlying

biology and the peer-reviewed literature

on this, nothing could be further from

the truth. We have distinct circuits in

the brain for aggression versus grief

and mourning. Those are non-over

overlapping. Now that doesn't mean that

you can't be sad and aggressive or in a

state of mourning and aggressive at the

same time. But the idea that sadness and

aggression are one in the same thing is

simply not true. And by understanding

that or perhaps by understanding that

irritability and aggression are not the

same thing, you'll be in a much better

position to apply some of the tools that

we will talk about in this episode in

order to be able to reduce or eliminate

or if it's adaptive to you to modulate

aggression. And yes, there are cases

where modulating your aggression, in

some cases even amplifying aggression

can be adaptive. One of the names that's

most associated with the formal study of

aggression is none other than Conrad

Loren. Conrad Loren

studied so-called imprinting behaviors

and fixed action pattern behaviors.

Patterns of behavior that could be

evoked by a single stimulus. The idea

that you can get a whole category of

behaviors like looking to somebody for

comfort and only them. The idea that

that you could get a huge category of

different behaviors in a bunch of

different contexts triggered by just the

presence of that person is remarkable

because what it suggested and what turns

out to be true is that there are neural

circuits, not just individual brain

areas, but collections of brain areas

that work together to engage a pattern

of behaviors. And that's the first

fundamental principle that we need to

define today. that when we talk about

aggression, we're talking about

activation of neural circuits, not

individual brain areas, but neural

circuits that get played out in sequence

like keys on a piano. But that playing

out in sequence means that aggression is

a verb. It has a beginning, a middle,

and an end. And it's a process. It's not

an event. And as you'll see, that turns

out to be very important in terms of

thinking about how one can halt

aggression, prevent it from happening

before it's initiated, or maybe even

prolonging aggression if that's what's

needed. Now, Conrad Loren had no real

knowledge of neural circuits. I mean,

obviously he knew there was this thing

that we call a brain and a nervous

system, and he knew that there were

chemicals in the brain and hormones and

things of that sort that were likely to

play a role, but he really didn't take

any measures to define what the neural

circuits were. But he did think about

what sorts of underlying processes could

drive something like aggression. And he

talked about one particular feature

that's especially important, and that's

this notion of a pressure. The idea that

yes, certain hormones will bias somebody

or an animal to be aggressive. Certain

neurotransmitter states, and you'll

learn what those are today, will bias

somebody to be more or less aggressive.

And yes, of course, there will be

historical features based on their

childhood, etc., etc. He understood that

there will be a constellation of things

that would drive people to be

aggressive. And he described a so-called

pressure, almost like a hydraulic

pressure. Just think about fluid

pressure in a small container being

pushed, push pushed until the can or the

container is ready to explode and how

multiple features, multiple variables

could impinge on that and create that

pressure. It turns out that's exactly

the way the system works. There is no

single brain area that flips the switch

for aggression. Although we'll soon talk

about a brain structure that generally

houses the propensity and the output of

aggression.

This notion of a hydraulic pressure that

can drive us toward aggressive behavior

or conversely can be very low pressure

and keep us in a state of

non-reactivity, maybe even passivity or

submissiveness is a very important

feature because it really captures the

essence of how neural circuits work when

we're talking about primitive behaviors

generally. And you can start to notice

this in yourself and in others. you can

start to notice when you are veering

toward aggression or when someone is

veering toward aggression, verbal or

physical. Now that veering is the

buildup of this hydraulic pressure that

Loren was referring to and it really

does have an underlying biological

basis. Now, it was some years later that

the first experiments came along which

really started to identify the brain

areas and the biological so-called

pressures that can induce aggressive

behavior. And the person that really

gets credit for this is a guy by the

name of Walter Hess who at that time was

working on cats. And I know that when

you say working on cats, a lot of people

would cringe. A lot of people have cats

as pets. And certainly cats can be

delightful. Some people like them more.

Some people like them less. Most people

cringe at the idea of doing experiments

on cats. In the time of Hess, very few

laboratories worked on mice. Most

laboratories worked on cats or rats. So

when I say he was working on cats, I

realize that probably evokes some

negative emotions in some of you, maybe

even aggression in some of you. What we

can do, however, is look at the data and

make use of the data in terms of our

understanding.

What Hess did was he had cats that were

awake and he was able to lower a

stimulating electrode into their brain.

Now keep in mind that the brain does not

have any pain sensors. So after a small

hole is made in the skull, electrodes

are lowered into the brain. This is

what's done commonly in human

neurosurgery. He was trying to identify

brain regions that could generate entire

categories of behavior. Eventually, his

electrode landed in a site and he

provided electrical stimulation to the

cat that caused this otherwise passive

purring relaxing cat to suddenly go into

an absolute rage when he stimulated this

particular brain area. And the fact that

when he turned off the stimulation of

this particular brain area, the cat very

quickly within seconds went back to

being passive calm kitty. And later

experiments done in mice but also in

humans confirmed that indeed stimulation

of this brain area evoked not just

behavioral aggression but also

subjective feelings of aggression and

anger. So what was this incredible brain

area? The so-called VMH or ventromedial

hypothalamus. The ventromedial

hypothalamus is a nucleus, meaning a

small collection of neurons, only about

1,500 neurons on one side of your brain

and a matching 1,500 neurons on the

other side of your brain. And that

combined 3,000 neurons or so is

sufficient to generate aggressive

behavior of the sort that Hess observed

in the cat. And believe it or not, when

you see somebody who's in a act of rage

or in an act of verbal aggression or in

an act of defensive aggression,

protecting their family or loved ones or

country, etc. Almost certainly those

neurons are engaged in that behavior.

Experiments done by David Anderson's lab

at Caltech were really the first to

parse the fine circuitry and to really

show that the ventromedial hypothalamus

is both necessary and sufficient for

aggressive behavior. What they did was

they identified where the ventromedial

hypothalamus was in the mouse. That was

pretty straightforward to do. It was

sort of known before they started these

experiments. And then they analyzed

which genes

meaning which DNA which of course

becomes RNA and RNA becomes protein.

Which DNA and therefore which proteins

are expressed in particular cells of the

ventromedial hypothalamus. And it turns

out that there's a particular category

of neurons in the vententral medial

hypothalamus that make an estrogen

receptor.

And it is those neurons in particular

that are responsible for generating

aggressive behavior. How did they know

this? Well, they used a tool that's

actually been described by a previous

guest of this podcast. We had an episode

with the psychiatrist and bioengineer

and my colleague at Stanford School of

Medicine, Carl Dyeroth. He and others

have developed tools that allow people

to control the activity of neurons

essentially by remote control by shining

light on those neurons. So in the

context of an experiment on a mouse,

which is what David's lab did, and these

were the beautiful experiments of Dulin,

who's now in her own laboratory at New

York University, put a little fiber

optic cable down into the hypothalamus

of the mouse. The mouse is able to move

around in its cage, freely moving, even

though it has a little tether. This

little wire, it's a very thin wire. And

that little thin wire is actually a

little what we call optrode. And the

experimentalist in this case Dou was

able to stimulate the turning on of a

little bit of blue light. And that blue

light activated only those estrogen

receptor neurons in only the

ventromedial hypothalamus. And the way

she was able to do that is she had

introduced a gene that had been

developed by our friend Carl Daiseroth

that allows light to trigger electrical

activity in those neurons. So if any of

that is confusing or if all of that is

confusing, here's the experiment.

There's a mouse in a cage has a little

wire coming out of its head. It doesn't

notice, believe it or not. We know this

because it's still eating and mating and

doing all the things that mice like to

do on a daily basis and sleeping, etc.

And the mere pressing of a button will

activate a little bit of light released

at the end of that wire. That light

activates particular neurons. In this

case, it's the estrogen receptor

containing neurons in only the

ventromedial hypothalamus. A large

number of experiments were done, but the

first experiment really was to put the

male mouse in with a female mouse who's

in the so-called receptive phase of

estrus. That is she will allow mating.

And he starts mating with her. and they

go through the standard repertoire of

mating behaviors that you observe in

mice, mounting, thrusting, intrammission

as it's called in the mouse sex world.

Um, well, I guess I don't know what the

mice call it, but that's what the

experimenters call it. And then

afterwards that he will dismount. But

about halfway through the behavior, Dau

turned on the light to stimulate these

estrogen receptor containing neurons

only in the male mouse. And what she

observed was incredibly dramatic. The

male mouse ceases from trying to mate

with the female mouse and immediately

tries to kill the female mouse. He

starts attacking her. Then she turns off

the light. The male stops and goes back

to trying to mate with the female mouse.

So I'm sure all of this was very

confusing and disturbing to the female

mouse. Nonetheless, that was the

repertoire. These are such dramatic

shifts in behavior triggered only by the

activation of only this small set of

neurons within the ventromedial

hypothalamus. The shift in behavior is

almost instantaneous. Occurs within

seconds if not milliseconds, thousands

of a second. The next experiment that

she did was to put a male mouse with

this stimulation with light capability

in its ventromedial hypothalamus into a

cage alone, but with a rubber glove

filled with air or water. Then she

stimulates the activation of these

ventromedial hypothalamus neurons and

the mouse immediately tries to kill the

glove. It goes into a rage attacking the

glove as if it were another mouse or

some other animate object. But of

course, it's an inanimate object. It's

just a rubber glove. She stops the

stimulation and the mouse immediately

goes back to being completely calm or at

least not attacking. Again, we don't

know what the mouse was feeling.

Subsequent experiments done by Dulin in

her own laboratory and other

laboratories have shown that the

ventromedial hypothalamus is connected

with a bunch of other brain areas. One

of them that I want to call out now is

the so-called P AG, the perryqueductal

gray nucleus. This is a large structure

in the back of the brain that houses

things like neurons that can create

opioids. We all know of the opioid

crisis, but these are neurons that can

produce endogenous means made by the

body chemicals that can cause pain

relief. You could understand why that

might occur in a circuit for aggression,

right? Even if one is the aggressor,

it's likely that they may incur some

physical damage and they'd want some

pain relief.

The Pag also is connected to a number of

neural circuits that eventually through

several processing stages stations,

excuse me, arrive at things like the

jaws. And in fact, stimulation of the

ventrome hypothalamus can evoke biting

and aggressive biting behavior. Now,

aggressive biting behavior is

particularly interesting because in

humans and especially in human children,

biting is something that while young

children might do as a form of

aggression, tends to disappear pretty

early in childhood. And if it doesn't,

it's often seen as a mark of pathology.

I think there is general agreement in

the psychology community and the

psychiatric community that past a

certain age the using of one's teeth to

impart aggress aggression and damage on

others is a particularly primitive and

troubling or at least for the observer

or the person experiences a pretty

disturbing event. Dou's lab has shown

that activation of the vententral medial

hypothalamus triggers a downstream

circuit in the perryqueductal gray which

then triggers a whole other set of

circuits of fixed action patterns. Here

we are back to Lorenzans with fixed

action patterns including swinging of

the limbs, right? Punching. This

wouldn't necessarily be controlled

punching, but also biting behavior. So,

it's remarkable to me at least that we

have circuits in our brain that can

evoke violent use of things like our

mouth or violent use of things like our

limbs that of course could be used for

things like singing or kissing or eating

or you know justiculating in any kind of

polite or impolite way. The point here

is that neural circuits not individual

brain areas evoke the constellation of

behaviors that we call aggression. Now,

many of you are probably puzzled or at

least should be because I've been

talking about this highly specialized

brain area, the ventromedial

hypothalamus, and this highly

specialized subcategory of neurons in

the ventromedial hypothalamus. These

neurons that make estrogen receptor and

yet the activation of those cells

triggers dramatic and immediate

aggression both in males and in females

and both against males and against

females. So, what's going on here? Most

of us think about estrogen and we don't

immediately think of aggression. Most of

us hear testosterone and we might think

about aggression. To make a long story

short and to dispel a still

unfortunately very common myth,

testosterone does not increase

aggressiveness.

Testosterone increases proactivity and

the willingness to lean into effort in

competitive scenarios. If people are

given testosterone or if you look at

people who have different le levels,

excuse me, of testosterone indogenously

that they naturally make, what you'll

find is that testosterone tends to

increase competitiveness, but not just

in aggressive scenarios. So, if somebody

is already aggressive, giving them

testosterone will have the tendency to

make them more aggressive. If somebody

however is very benevolent and

altruistic, giving them testosterone

will make them more benevolent and

altruistic at least up to a point. Turns

out there's evidence that in certain

context estrogen can make people more

aggressive. So what's going on here?

Well, what's going on is that

testosterone can be converted into

estrogen through a process called

aromatization. There's an enzyme called

aromatase. Anytime you have a word that

ends in asse at least if it's in the

context of biology it's almost always

not always but almost always an enzyme.

So arom the aromatase enzyme converts

testosterone into estrogen and it is

actually testosterone aromatized

converted into estrogen and then binding

to these estrogen containing neurons in

the ventromedial hypothalamus that

triggers aggression. I want to repeat

that it is not testosterone itself that

triggers aggression. It is testosterone

aromatized into estrogen within the

brain and binding to these estrogen

receptor containing neurons in the

vententral medial hypothalamus that

evokes aggression and dramatic

aggression at that. Now this effect of

estrogen causing aggression in the brain

is very robust. So much so that if you

take a mouse that lacks the aromatase

enzyme or a human that lacks the

aromatase enzyme and they do exist then

there is a reduction in overall

aggression despite high levels of

testosterone. It doesn't matter how much

you increase testosterone or any of its

other derivatives you do not observe

this aggression. This runs counter to

everything that we know and think about

the role of testosterone. So the next

time somebody says testosterone makes

people aggressive, you can say ah no

actually it's estrogen that makes people

aggressive and animals aggressive for

that matter. Now of course it is the

case that because males have relatively

less estrogen circulating in their brain

and body than females, right? because

they have testes, not ovaries. That

testosterone is required in the first

place in order to be converted into

estrogen to activate this aggressive

circuit involving these estrogen

receptor containing neurons in the

ventromedial hypothalamus. So, we've

established that it's not testosterone,

but testosterone converted into estrogen

that activates these circuits for

aggression. Nonetheless, it's still

surprising, right? Right? I mean, most

of us don't think about a estrogen as

the hormone that stimulates aggression,

but turns out it's all contextual. There

are beautiful data showing that whether

or not estrogen stimulates aggression

can be powerfully modulated by whether

or not days are short or days are long.

In other words, whether or not there's a

lot of sunshine or not. Day length is

converted into hormonal signals and

chemical signals. And the primary

hormonal and chemical signals involve

melatonin and dopamine and also the

stress hormones. So to make a very long

story short, in the long days where we

get a lot of sunlight both in our eyes

and on our skin, melatonin levels are

reduced. Melatonin is a hormone that

tends to produce states of sleepiness

and quiescence. It also tends to

activate pathways that tend to reduce uh

things like breeding and sexual

behavior. In long days, dopamine is

increased. Dopamine is a molecule

associated with feelings of well-being

and motivation and the desire to seek

out all sorts of things. And in long

days, provided we're getting enough

sunlight on our skin and to our eyes,

the stress hormones, especially cortisol

and some of the other stress hormones

are reduced in levels. If estrogen

levels are increased experimentally

under long day conditions, it does not

evoke aggression. However, in short

days, if estrogen is increased, there is

a heightened predisposition for

aggression. And that makes perfect

sense. If you think about what short

days do to the biology of your brain and

body, the melatonin signal goes up.

There's more melatonin circulating for

more of each 24-hour cycle. Stress

hormones are circulating more. Why?

Short days tend to be associated with

winter. In winter, we are bombarded with

more bacteria and viruses because

bacteria and viruses actually survive

better in cold than they do in heat. So,

shorter days are conducive to

aggression, not because days are short

per se, but because stress hormone

levels are higher, and because dopamine

levels are lower. Now, here's where all

of this starts to converge on a very

clear biological picture, a very clear

psychological picture, and indeed a very

clear set of tools that we can think

about and use. Under conditions where

cortisol is high, where the stress

hormone is elevated, and under

conditions where the neurom modulator

serotonin is reduced, there is a greater

propensity for estrogen to trigger

aggression. For males who make a lot of

testosterone relative to estrogen, you

have to swap in your mind this idea that

if testosterone is high, that means that

estrogen is low. Because if testosterone

is high, there is going to be some

aromatization, that conversion of

testosterone to estrogen. So anytime you

hear that testosterone is high, you

should think testosterone is high in the

body and perhaps estrogen is low in the

body, but that means that there's going

to be heightened levels of estrogen in

the brain and therefore increased

propensity for aggression. In females

who generally make less testosterone

relative to estrogen, there is

sufficient estrogen already present to

trigger aggression. So both males and

females are primed for aggression. But

that's riding on a context and that

context of whether or not you get a

tendency for aggression or not depends

on whether or not cortisol is high or

low. And I'm telling you that if

cortisol is relatively higher in any

individual, there's going to be a tilt,

an increase in that hydraulic pressure

that Loren talked about toward

aggression.

And if serotonin, the neurom modulator

that is associated with feelings of

well-being and sometimes even of slight

passivity, but certainly of well-being,

if serotonin is low, there's also going

to be a further shift towards an

aggressive tendency. So if we return to

Lorenz's hydraulic pressure model of

aggression and other internal states, we

realize that external stimula, things

that we hear, things that we see, for

instance, someone saying something

upsetting or us seeing somebody do

something that we don't like to others

or to us, as well as our internal state,

our subjective feelings of well-being,

but also our stress level, our feelings

of whether or not we have enough

resources and are content. with what we

have all of that is converging on this

thing that we call internal state and

creating this pressure of either to be

more aggressive or less aggressive. Now

we have some major players feeding into

that final pathway that question of

whether or not will we hit the other

person. Will we say the thing that is

considered aggressive? Will we not say

it? Again, there are many things

funneling into that question and

dictating whether or not the answer is

absolutely I'll fight back or I'm going

to attack them even unprovoked. we

really can boil them down to just a few

common elements. And I'm telling you

that those elements are whether or not

cortisol levels are relatively lower or

relatively higher. Again, relatively

higher is going to tend to make people

more reactive. Why? Because

reactivity is really a function of the

autonomic nervous system, which is sort

of like a seessaw that oscillates

between the so-called sympathetic

arm of the autonomic nervous system,

which tends to put us into a state of

readiness through the release of

adrenaline. Cortisol and adrenaline when

they're circulating in the brain and

body make us more likely to move and to

react and to speak. It's actually what

will induce a kind of low-level tremor,

which is an anticipatory tremor to be

able to move more quickly. Right? a body

in motion is more easily set into

further motion. That is, and in terms of

keeping cortisol in a range that's

healthy and doesn't bias someone toward

high levels of aggression and

irritability, that's again going to be

set by a number of larger modulators or

contextual cues. And I've talked about

some of those on the podcast, but I'll

just briefly recap them now. Obviously,

getting sunlight in your eyes early in

the day and as much sunlight as you

safely can in your eyes throughout the

day is going to be important. Again,

because of this effect of estrogen in

long days, not increasing aggression.

However, in shorter days, estrogen

increases aggression because of the

increase in cortisol observed in short

days. Another way to reduce cortisol was

discussed in our episode on heat and the

use of sauna and heat, but also hot

baths. It turns out that hot baths and

sauna can be very beneficial for

reducing cortisol. All the details on

that are included in the episode on heat

and it's timestamped. So you can go

directly to that if you want to learn

about the temperatures and the various

durations. But to just give a uh

synopsis of that a 20 minute sauna at

anywhere from 80 to 100° C is going to

be beneficial for reducing cortisol. If

you don't have access to a sauna, you

could do a hot bath. And of course, some

of you may be interested in exploring

the supplementation route. And for

reductions in cortisol, really the uh

chief player there is ashwagandha, which

is known to decrease cortisol fairly

potently. I should just warn you that if

you're going to use ashwagandha in order

to reduce cortisol, first of all, check

with your doctor or healthcare provider

before adding or subtracting anything

from your supplementation or health

regimen. Of course, I don't just say

that to protect us. I say that to

protect you. You are responsible for

your health, what you take and what you

don't take. Chronic supplementation with

ashwagandha can have some not so great

effects of disruption of other hormone

pathways and neurotransmitter pathways.

So the limit seems to be about 2 weeks

of of regular use before you'd want to

take a break of about 2 weeks. So

ashwagandha again a very potent

inhibitor of cortisol but with some

other effects as well. Don't use it

chronically for longer than 2 weeks. But

if your goal is to reduce cortisol,

let's say you're going through a period

of increased irritability and aggressive

tendency, maybe you're also not getting

as much light as you would like. And

perhaps also if there are other um

circumstantial things leading you

towards more aggressiveness and your

goal is to reduce aggressiveness, that

can be potentially helpful. And in light

of all this stuff about cortisol and

estrogen and daylength,

I should mention that there are in fact

some people who have a genetic

predisposition to be more irritable and

aggressive. There is a genetic variant

present in certain people that adjusts

their estrogen receptor sensitivity

and that estrogen receptor sensitivity

can result in increased levels of

aggression. sometimes dramatic

increases. However, and also very

interestingly, photo period, meaning

daylength is a strong modulator of

whether or not that aggressiveness turns

up or not. Whether or not that person

with the particular gene variant is more

aggressive or not depends on how long

the day is and how long the night is.

One particular study that I like that

references this is trainer at all. The

title of the study is photo period

reverses the effects of estrogens on

male aggression via genomic and

non-genomic pathways. This was a paper

published in the proceedings of the

National Academy of Sciences. It really

points to the fact that rarely is it the

case that just one gene will cause

somebody to be hyperaggressive.

Almost always there's going to be an

interplay between genetics and

environment. And as environment changes,

such as daylength changes and the length

of night changes, so too will the

tendency for people with a given genetic

variant to be more aggressive or not.

Now, of course, in the absence of

detailed genetic testing for this

particular estrogen receptor variant,

most people, I'm guessing you are

probably not walking around knowing that

you have this gene or not.

Regardless, I think it's important to

pay attention to how you feel at

different times of year depending on

whether or not summer, whether or not

it's winter, whether or not you're

getting sufficient sunlight, meaning

viewing sufficient sunlight or not,

whether or not you're getting sufficient

sunlight exposure to your skin or not,

whether or not you're indoors all the

time. Generally, those things correlate

with season, but not always. You can go

through long bouts of you know hard work

in the summer months when days are long

but you're indoors a lot and getting a

lot of fluorescent light exposure late

in the evening and perhaps that's when

you're feeling more aggressive. So we

have to be careful about drawing a

onetoone relationship between any

biological feature and certainly

psychological or behavioral feature like

aggressiveness. But it's I believe

helpful to know that these genetic

biases exist. How they play out again

they shift our biology in in a general

thematic direction. They don't change

one thing. They change a variety of

things that bias us toward or away from

certain psychological and behavioral

outcomes and the various things that we

can do in order to offset them. And we

described those earlier in terms of

trying to keep cortisol low by getting

sufficient sunlight regardless of time

of year and regardless of whether or not

you happen to have this particular

genetic variant. I want to share with

you a study that's focused on kids, but

that has important ramifications for

adults as well. There are many kids out

there that suffer from so-called

attention deficit hyperactivity disorder

or ADHD. There are also many adults we

are finding that are suffering from

ADHD. In any event, the study I'm about

to share with you explored how a

particular pattern of supplementation in

kids with ADHD was able to reduce

aggressive episodes and impulsivity and

increase self-regulation.

And the title of the study is efficacy

of carnitine in the treatment of

children with attention deficit

hyperactivity disorder. even though they

put carnitine in the title that what

they focused on was whether or not a

cetal LC carnitine supplementation could

somehow adjust the behavioral tendency

of these kids with ADHD. And to make a

long story short, indeed it did. There

was a very significant effect of acetyl

carnitine supplementation on improving

some of the symptomology symptomology,

excuse me, of ADHD. This was a

randomized double blind placeboc control

double crossover study. They showed

significant reductions in their

so-called total problem score. The total

problem score is a well-established

measure of behavioral problems in kids

with ADHD and I should say adults with

ADHD. Reductions in attentional problems

overall reductions in delinquency and

most important for sake of today's

discussion significant reductions in

aggressive behavior. They were able to

confirm the shifts in alcarnitine

within the bloodstream of these kids.

that is they were able to correlate the

physiology with the psychological

changes. So studies such as this I think

are useful because they point to the

fact that

very seldom if ever will there be one

supplement or one nutritional change or

even one behavioral change that's going

to completely shift an individual from

being aggressive and impulsive. rather

that by combining different behavioral

regimens, by paying attention to things

like time of year and work conditions

and school conditions and overall levels

of stress and likely therefore levels of

cortisol, etc. that you can use

behaviors, diet, and supplementation as

a way to shift that overall internal

millu from one of providing a lot of

internal hydraulic pressure, as it's

been called throughout the episode,

toward aggressive impulsivity and relax

some of that hydraulic pressure and

reduce aggressive tendencies. Thank you

for joining me for our discussion about

the biology, psychology, and actionable

tools around aggression. And as always,

thank you for your interest in science.