For a really long time,

I had two mysteries
that were hanging over me.

I didn't understand them

and, to be honest, I was quite afraid
to look into them.

The first mystery was, I'm 40 years old,

and all throughout my lifetime,
year after year,

serious depression and anxiety have risen,

in the United States, in Britain,

and across the Western world.

And I wanted to understand why.

Why is this happening to us?

Why is it that with each year that passes,

more and more of us are finding it harder
to get through the day?

And I wanted to understand this
because of a more personal mystery.

When I was a teenager,

I remember going to my doctor

and explaining that I had this feeling,
like pain was leaking out of me.

I couldn't control it,

I didn't understand why it was happening,

I felt quite ashamed of it.

And my doctor told me a story

that I now realize was well-intentioned,

but quite oversimplified.

Not totally wrong.

My doctor said, "We know
why people get like this.

Some people just naturally get
a chemical imbalance in their heads --

you're clearly one of them.

All we need to do is give you some drugs,

it will get your chemical
balance back to normal."

So I started taking a drug
called Paxil or Seroxat,

it's the same thing with different names
in different countries.

And I felt much better,
I got a real boost.

But not very long afterwards,

this feeling of pain started to come back.

So I was given higher and higher doses

until, for 13 years, I was taking
the maximum possible dose

that you're legally allowed to take.

And for a lot of those 13 years,
and pretty much all the time by the end,

I was still in a lot of pain.

And I started asking myself,
"What's going on here?

Because you're doing everything

you're told to do by the story
that's dominating the culture --

why do you still feel like this?"

So to get to the bottom
of these two mysteries,

for a book that I've written

I ended up going on a big journey
all over the world,

I traveled over 40,000 miles.

I wanted to sit with the leading
experts in the world

about what causes depression and anxiety

and crucially, what solves them,

and people who have come through
depression and anxiety

and out the other side
in all sorts of ways.

And I learned a huge amount

from the amazing people
I got to know along the way.

But I think at the heart
of what I learned is,

so far, we have scientific evidence

for nine different causes
of depression and anxiety.

Two of them are indeed in our biology.

Your genes can make you
more sensitive to these problems,

though they don't write your destiny.

And there are real brain changes
that can happen when you become depressed

that can make it harder to get out.

But most of the factors
that have been proven

to cause depression and anxiety

are not in our biology.

They are factors in the way we live.

And once you understand them,

it opens up a very different
set of solutions

that should be offered to people

alongside the option
of chemical antidepressants.

For example,

if you're lonely, you're more likely
to become depressed.

If, when you go to work,
you don't have any control over your job,

you've just got to do what you're told,

you're more likely to become depressed.

If you very rarely get out
into the natural world,

you're more likely to become depressed.

And one thing unites a lot of the causes
of depression and anxiety

that I learned about.

Not all of them, but a lot of them.

Everyone here knows

you've all got natural
physical needs, right?

Obviously.

You need food, you need water,

you need shelter, you need clean air.

If I took those things away from you,

you'd all be in real trouble, real fast.

But at the same time,

every human being
has natural psychological needs.

You need to feel you belong.

You need to feel your life
has meaning and purpose.

You need to feel that people
see you and value you.

You need to feel you've got
a future that makes sense.

And this culture we built
is good at lots of things.

And many things are better
than in the past --

I'm glad to be alive today.

But we've been getting less and less good

at meeting these deep,
underlying psychological needs.

And it's not the only thing
that's going on,

but I think it's the key reason
why this crisis keeps rising and rising.

And I found this really hard to absorb.

I really wrestled with the idea

of shifting from thinking of my depression
as just a problem in my brain,

to one with many causes,

including many in the way we're living.

And it only really began
to fall into place for me

when one day, I went to interview
a South African psychiatrist

named Dr. Derek Summerfield.

He's a great guy.

And Dr. Summerfield
happened to be in Cambodia in 2001,

when they first introduced
chemical antidepressants

for people in that country.

And the local doctors, the Cambodians,
had never heard of these drugs,

so they were like, what are they?

And he explained.

And they said to him,

"We don't need them,
we've already got antidepressants."

And he was like, "What do you mean?"

He thought they were going to talk about
some kind of herbal remedy,

like St. John's Wort, ginkgo biloba,
something like that.

Instead, they told him a story.

There was a farmer in their community
who worked in the rice fields.

And one day, he stood on a land mine

left over from the war
with the United States,

and he got his leg blown off.

So they him an artificial leg,

and after a while, he went back
to work in the rice fields.

But apparently, it's super painful
to work under water

when you've got an artificial limb,

and I'm guessing it was pretty traumatic

to go back and work in the field
where he got blown up.

The guy started to cry all day,

he refused to get out of bed,

he developed all the symptoms
of classic depression.

The Cambodian doctor said,

"This is when we gave him
an antidepressant."

And Dr. Summerfield said,
"What was it?"

They explained that they went
and sat with him.

They listened to him.

They realized that his pain made sense --

it was hard for him to see it
in the throes of his depression,

but actually, it had perfectly
understandable causes in his life.

One of the doctors, talking to the people
in the community, figured,

"You know, if we bought this guy a cow,

he could become a dairy farmer,

he wouldn't be in this position
that was screwing him up so much,

he wouldn't have to go
and work in the rice fields."

So they bought him a cow.

Within a couple of weeks,
his crying stopped,

within a month, his depression was gone.

They said to doctor Summerfield,

"So you see, doctor, that cow,
that was an antidepressant,

that's what you mean, right?"

(Laughter)

(Applause)

If you'd been raised to think
about depression the way I was,

and most of the people here were,

that sounds like a bad joke, right?

"I went to my doctor
for an antidepressant,

she gave me a cow."

But what those Cambodian
doctors knew intuitively,

based on this individual,
unscientific anecdote,

is what the leading
medical body in the world,

the World Health Organization,

has been trying to tell us for years,

based on the best scientific evidence.

If you're depressed,

if you're anxious,

you're not weak, you're not crazy,

you're not, in the main,
a machine with broken parts.

You're a human being with unmet needs.

And it's just as important to think here
about what those Cambodian doctors

and the World Health Organization
are not saying.

They did not say to this farmer,

"Hey, buddy, you need
to pull yourself together.

It's your job to figure out
and fix this problem on your own."

On the contrary, what they said is,

"We're here as a group
to pull together with you,

so together, we can figure out
and fix this problem."

This is what every depressed person needs,

and it's what every
depressed person deserves.

This is why one of the leading
doctors at the United Nations,

in their official statement
for World Health Day,

couple of years back in 2017,

said we need to talk less
about chemical imbalances

and more about the imbalances
in the way we live.

Drugs give real relief to some people --

they gave relief to me for a while --

but precisely because this problem
goes deeper than their biology,

the solutions need to go much deeper, too.

But when I first learned that,

I remember thinking,

"OK, I could see
all the scientific evidence,

I read a huge number of studies,

I interviewed a huge number of the experts
who were explaining this,"

but I kept thinking, "How can we
possibly do that?"

The things that are making us depressed

are in most cases more complex
than what was going on

with this Cambodian farmer.

Where do we even begin with that insight?

But then, in the long journey for my book,

all over the world,

I kept meeting people
who were doing exactly that,

from Sydney, to San Francisco,

to São Paulo.

I kept meeting people
who were understanding

the deeper causes
of depression and anxiety

and, as groups, fixing them.

Obviously, I can't tell you
about all the amazing people

I got to know and wrote about,

or all of the nine causes of depression
and anxiety that I learned about,

because they won't let me give
a 10-hour TED Talk --

you can complain about that to them.

But I want to focus on two of the causes

and two of the solutions
that emerge from them, if that's alright.

Here's the first.

We are the loneliest society
in human history.

There was a recent study
that asked Americans,

"Do you feel like you're no longer
close to anyone?"

And 39 percent of people
said that described them.

"No longer close to anyone."

In the international
measurements of loneliness,

Britain and the rest of Europe
are just behind the US,

in case anyone here is feeling smug.

(Laughter)

I spent a lot of time discussing this

with the leading expert
in the world on loneliness,

an incredible man
named professor John Cacioppo,

who was at Chicago,

and I thought a lot about one question
his work poses to us.

Professor Cacioppo asked,

"Why do we exist?

Why are we here, why are we alive?"

One key reason

is that our ancestors
on the savannas of Africa

were really good at one thing.

They weren't bigger than the animals
they took down a lot of the time,

they weren't faster than the animals
they took down a lot of the time,

but they were much better
at banding together into groups

and cooperating.

This was our superpower as a species --

we band together,

just like bees evolved to live in a hive,

humans evolved to live in a tribe.

And we are the first humans ever

to disband our tribes.

And it is making us feel awful.

But it doesn't have to be this way.

One of the heroes in my book,
and in fact, in my life,

is a doctor named Sam Everington.

He's a general practitioner
in a poor part of East London,

where I lived for many years.

And Sam was really uncomfortable,

because he had loads of patients

coming to him with terrible
depression and anxiety.

And like me, he's not opposed
to chemical antidepressants,

he thinks they give
some relief to some people.

But he could see two things.

Firstly, his patients were depressed
and anxious a lot of the time

for totally understandable
reasons, like loneliness.

And secondly, although the drugs
were giving some relief to some people,

for many people,
they didn't solve the problem.

The underlying problem.

One day, Sam decided
to pioneer a different approach.

A woman came to his center,
his medical center,

called Lisa Cunningham.

I got to know Lisa later.

And Lisa had been shut away in her home
with crippling depression and anxiety

for seven years.

And when she came to Sam's center,
she was told, "Don't worry,

we'll carry on giving you these drugs,

but we're also going to prescribe
something else.

We're going to prescribe for you
to come here to this center twice a week

to meet with a group of other
depressed and anxious people,

not to talk about how miserable you are,

but to figure out something
meaningful you can all do together

so you won't be lonely and you won't feel
like life is pointless."

The first time this group met,

Lisa literally started
vomiting with anxiety,

it was so overwhelming for her.

But people rubbed her back,
the group started talking,

they were like, "What could we do?"

These are inner-city,
East London people like me,

they didn't know anything about gardening.

They were like, "Why don't we
learn gardening?"

There was an area
behind the doctors' offices

that was just scrubland.

"Why don't we make this into a garden?"

They started to take books
out of the library,

started to watch YouTube clips.

They started to get
their fingers in the soil.

They started to learn
the rhythms of the seasons.

There's a lot of evidence

that exposure to the natural world

is a really powerful antidepressant.

But they started to do something
even more important.

They started to form a tribe.

They started to form a group.

They started to care about each other.

If one of them didn't show up,

the others would go
looking for them -- "Are you OK?"

Help them figure out
what was troubling them that day.

The way Lisa put it to me,

"As the garden began to bloom,

we began to bloom."

This approach is called
social prescribing,

it's spreading all over Europe.

And there's a small,
but growing body of evidence

suggesting it can produce real
and meaningful falls

in depression and anxiety.

And one day, I remember
standing in the garden

that Lisa and her once-depressed
friends had built --

it's a really beautiful garden --

and having this thought,

it's very much inspired by a guy
called professor Hugh Mackay in Australia.

I was thinking, so often
when people feel down in this culture,

what we say to them -- I'm sure
everyone here said it, I have --

we say, "You just need
to be you, be yourself."

And I've realized, actually,
what we should say to people is,

"Don't be you.

Don't be yourself.

Be us, be we.

Be part of a group."

(Applause)

The solution to these problems

does not lie in drawing
more and more on your resources

as an isolated individual --

that's partly what got us in this crisis.

It lies on reconnecting
with something bigger than you.

And that really connects
to one of the other causes

of depression and anxiety
that I wanted to talk to you about.

So everyone knows

junk food has taken over our diets
and made us physically sick.

I don't say that
with any sense of superiority,

I literally came to give
this talk from McDonald's.

I saw all of you eating that
healthy TED breakfast, I was like no way.

But just like junk food has taken over
our diets and made us physically sick,

a kind of junk values
have taken over our minds

and made us mentally sick.

For thousands of years,
philosophers have said,

if you think life is about money,
and status and showing off,

you're going to feel like crap.

That's not an exact quote
from Schopenhauer,

but that is the gist of what he said.

But weirdly, hardy anyone
had scientifically investigated this,

until a truly extraordinary person
I got to know, named professor Tim Kasser,

who's at Knox College in Illinois,

and he's been researching this
for about 30 years now.

And his research suggests
several really important things.

Firstly, the more you believe

you can buy and display
your way out of sadness,

and into a good life,

the more likely you are to become
depressed and anxious.

And secondly,

as a society, we have become
much more driven by these beliefs.

All throughout my lifetime,

under the weight of advertising
and Instagram and everything like them.

And as I thought about this,

I realized it's like we've all been fed
since birth, a kind of KFC for the soul.

We've been trained to look for happiness
in all the wrong places,

and just like junk food
doesn't meet your nutritional needs

and actually makes you feel terrible,

junk values don't meet
your psychological needs,

and they take you away from a good life.

But when I first spent time
with professor Kasser

and I was learning all this,

I felt a really weird mixture of emotions.

Because on the one hand,
I found this really challenging.

I could see how often
in my own life, when I felt down,

I tried to remedy it with some kind of
show-offy, grand external solution.

And I could see why that
did not work well for me.

I also thought,
isn't this kind of obvious?

Isn't this almost like banal, right?

If I said to everyone here,

none of you are going to lie
on your deathbed

and think about all the shoes you bought
and all the retweets you got,

you're going to think about moments

of love, meaning
and connection in your life.

I think that seems almost like a cliché.

But I kept talking
to professor Kasser and saying,

"Why am I feeling
this strange doubleness?"

And he said, "At some level,
we all know these things.

But in this culture,
we don't live by them."

We know them so well
they've become clichés,

but we don't live by them.

I kept asking why, why would we know
something so profound,

but not live by it?

And after a while,
professor Kasser said to me,

"Because we live in a machine

that is designed to get us to neglect
what is important about life."

I had to really think about that.

"Because we live in a machine

that is designed to get us
to neglect what is important about life."

And professor Kasser wanted to figure out
if we can disrupt that machine.

He's done loads of research into this;

I'll tell you about one example,

and I really urge everyone here
to try this with their friends and family.

With a guy called Nathan Dungan,
he got a group of teenagers and adults

to come together for a series of sessions
over a period of time, to meet up.

And part of the point of the group

was to get people to think
about a moment in their life

they had actually found
meaning and purpose.

For different people,
it was different things.

For some people, it was playing music,
writing, helping someone --

I'm sure everyone here
can picture something, right?

And part of the point of the group
was to get people to ask,

"OK, how could you dedicate
more of your life

to pursuing these moments
of meaning and purpose,

and less to, I don't know,
buying crap you don't need,

putting it on social media
and trying to get people to go,

'OMG, so jealous!'"

And what they found was,

just having these meetings,

it was like a kind of Alcoholics Anonymous
for consumerism, right?

Getting people to have these meetings,
articulate these values,

determine to act on them
and check in with each other,

led to a marked shift in people's values.

It took them away from this hurricane
of depression-generating messages

training us to seek happiness
in the wrong places,

and towards more meaningful
and nourishing values

that lift us out of depression.

But with all the solutions that I saw
and have written about,

and many I can't talk about here,

I kept thinking,

you know: Why did it take me so long
to see these insights?

Because when you explain them to people --

some of them are more
complicated, but not all --

when you explain this to people,
it's not like rocket science, right?

At some level, we already
know these things.

Why do we find it so hard to understand?

I think there's many reasons.

But I think one reason is
that we have to change our understanding

of what depression
and anxiety actually are.

There are very real
biological contributions

to depression and anxiety.

But if we allow the biology
to become the whole picture,

as I did for so long,

as I would argue our culture
has done pretty much most of my life,

what we're implicitly saying to people
is, and this isn't anyone's intention,

but what we're implicitly
saying to people is,

"Your pain doesn't mean anything.

It's just a malfunction.

It's like a glitch in a computer program,

it's just a wiring problem in your head."

But I was only able to start
changing my life

when I realized your depression
is not a malfunction.

It's a signal.

Your depression is a signal.

It's telling you something.

(Applause)

We feel this way for reasons,

and they can be hard to see
in the throes of depression --

I understand that really well
from personal experience.

But with the right help,
we can understand these problems

and we can fix these problems together.

But to do that,

the very first step

is we have to stop insulting these signals

by saying they're a sign of weakness,
or madness or purely biological,

except for a tiny number of people.

We need to start
listening to these signals,

because they're telling us
something we really need to hear.

It's only when we truly
listen to these signals,

and we honor these signals
and respect these signals,

that we're going to begin to see

the liberating, nourishing,
deeper solutions.

The cows that are waiting all around us.

Thank you.

(Applause)