I want you to imagine this for a moment.

Two men, Rahul and Rajiv,

living in the same neighborhood,

from the same educational background, similar occupation,

and they both turn up at their local accident emergency

complaining of acute chest pain.

Rahul is offered a cardiac procedure,

but Rajiv is sent home.

What might explain the difference in the experience

of these two nearly identical men?

Rajiv suffers from a mental illness.

The difference in the quality of medical care

received by people with mental illness is one of the reasons

why they live shorter lives

than people without mental illness.

Even in the best-resourced countries in the world,

this life expectancy gap is as much as 20 years.

In the developing countries of the world, this gap

is even larger.

But of course, mental illnesses can kill in more direct ways

as well. The most obvious example is suicide.

It might surprise some of you here, as it did me,

when I discovered that suicide is at the top of the list

of the leading causes of death in young people

in all countries in the world,

including the poorest countries of the world.

But beyond the impact of a health condition

on life expectancy, we're also concerned

about the quality of life lived.

Now, in order for us to examine the overall impact

of a health condition both on life expectancy

as well as on the quality of life lived, we need to use

a metric called the DALY,

which stands for a Disability-Adjusted Life Year.

Now when we do that, we discover some startling things

about mental illness from a global perspective.

We discover that, for example, mental illnesses are

amongst the leading causes of disability around the world.

Depression, for example, is the third-leading cause

of disability, alongside conditions such as

diarrhea and pneumonia in children.

When you put all the mental illnesses together,

they account for roughly 15 percent

of the total global burden of disease.

Indeed, mental illnesses are also very damaging

to people's lives, but beyond just the burden of disease,

let us consider the absolute numbers.

The World Health Organization estimates

that there are nearly four to five hundred million people

living on our tiny planet

who are affected by a mental illness.

Now some of you here

look a bit astonished by that number,

but consider for a moment the incredible diversity

of mental illnesses, from autism and intellectual disability

in childhood, through to depression and anxiety,

substance misuse and psychosis in adulthood,

all the way through to dementia in old age,

and I'm pretty sure that each and every one us

present here today can think of at least one person,

at least one person, who's affected by mental illness

in our most intimate social networks.

I see some nodding heads there.

But beyond the staggering numbers,

what's truly important from a global health point of view,

what's truly worrying from a global health point of view,

is that the vast majority of these affected individuals

do not receive the care

that we know can transform their lives, and remember,

we do have robust evidence that a range of interventions,

medicines, psychological interventions,

and social interventions, can make a vast difference.

And yet, even in the best-resourced countries,

for example here in Europe, roughly 50 percent

of affected people don't receive these interventions.

In the sorts of countries I work in,

that so-called treatment gap

approaches an astonishing 90 percent.

It isn't surprising, then, that if you should speak

to anyone affected by a mental illness,

the chances are that you will hear stories

of hidden suffering, shame and discrimination

in nearly every sector of their lives.

But perhaps most heartbreaking of all

are the stories of the abuse

of even the most basic human rights,

such as the young woman shown in this image here

that are played out every day,

sadly, even in the very institutions that were built to care

for people with mental illnesses, the mental hospitals.

It's this injustice that has really driven my mission

to try to do a little bit to transform the lives

of people affected by mental illness, and a particularly

critical action that I focused on is to bridge the gulf

between the knowledge we have that can transform lives,

the knowledge of effective treatments, and how we actually

use that knowledge in the everyday world.

And an especially important challenge that I've had to face

is the great shortage of mental health professionals,

such as psychiatrists and psychologists,

particularly in the developing world.

Now I trained in medicine in India, and after that

I chose psychiatry as my specialty, much to the dismay

of my mother and all my family members who

kind of thought neurosurgery would be

a more respectable option for their brilliant son.

Any case, I went on, I soldiered on with psychiatry,

and found myself training in Britain in some of

the best hospitals in this country. I was very privileged.

I worked in a team of incredibly talented, compassionate,

but most importantly, highly trained, specialized

mental health professionals.

Soon after my training, I found myself working

first in Zimbabwe and then in India, and I was confronted

by an altogether new reality.

This was a reality of a world in which there were almost no

mental health professionals at all.

In Zimbabwe, for example, there were just about

a dozen psychiatrists, most of whom lived and worked

in Harare city, leaving only a couple

to address the mental health care needs

of nine million people living in the countryside.

In India, I found the situation was not a lot better.

To give you a perspective, if I had to translate

the proportion of psychiatrists in the population

that one might see in Britain to India,

one might expect roughly 150,000 psychiatrists in India.

In reality, take a guess.

The actual number is about 3,000,

about two percent of that number.

It became quickly apparent to me that I couldn't follow

the sorts of mental health care models that I had been trained in,

one that relied heavily on specialized, expensive

mental health professionals to provide mental health care

in countries like India and Zimbabwe.

I had to think out of the box about some other model

of care.

It was then that I came across these books,

and in these books I discovered the idea of task shifting

in global health.

The idea is actually quite simple. The idea is,

when you're short of specialized health care professionals,

use whoever is available in the community,

train them to provide a range of health care interventions,

and in these books I read inspiring examples,

for example of how ordinary people had been trained

to deliver babies,

diagnose and treat early pneumonia, to great effect.

And it struck me that if you could train ordinary people

to deliver such complex health care interventions,

then perhaps they could also do the same

with mental health care.

Well today, I'm very pleased to report to you

that there have been many experiments in task shifting

in mental health care across the developing world

over the past decade, and I want to share with you

the findings of three particular such experiments,

all three of which focused on depression,

the most common of all mental illnesses.

In rural Uganda, Paul Bolton and his colleagues,

using villagers, demonstrated that they could deliver

interpersonal psychotherapy for depression

and, using a randomized control design,

showed that 90 percent of the people receiving

this intervention recovered as compared

to roughly 40 percent in the comparison villages.

Similarly, using a randomized control trial in rural Pakistan,

Atif Rahman and his colleagues showed

that lady health visitors, who are community maternal

health workers in Pakistan's health care system,

could deliver cognitive behavior therapy for mothers

who were depressed, again showing dramatic differences

in the recovery rates. Roughly 75 percent of mothers

recovered as compared to about 45 percent

in the comparison villages.

And in my own trial in Goa, in India, we again showed

that lay counselors drawn from local communities

could be trained to deliver psychosocial interventions

for depression, anxiety, leading to 70 percent

recovery rates as compared to 50 percent

in the comparison primary health centers.

Now, if I had to draw together all these different

experiments in task shifting, and there have of course

been many other examples, and try and identify

what are the key lessons we can learn that makes

for a successful task shifting operation,

I have coined this particular acronym, SUNDAR.

What SUNDAR stands for, in Hindi, is "attractive."

It seems to me that there are five key lessons

that I've shown on this slide that are critically important

for effective task shifting.

The first is that we need to simplify the message

that we're using, stripping away all the jargon

that medicine has invented around itself.

We need to unpack complex health care interventions

into smaller components that can be more easily

transferred to less-trained individuals.

We need to deliver health care, not in large institutions,

but close to people's homes, and we need to deliver

health care using whoever is available and affordable

in our local communities.

And importantly, we need to reallocate the few specialists

who are available to perform roles

such as capacity-building and supervision.

Now for me, task shifting is an idea

with truly global significance,

because even though it has arisen out of the