Challenges and Opportunities in Drug Demand Reduction (Continued)
Timothy P. Condon, Ph.D.
Associate Director
National Institute on Drug Abuse Department of Health and Human Services
United States
There are many reasons people take drugs.
One is to feel good. And that’s often the people
who are sensation seeking and want to feel
better. Those are people who are taking drugs
to help to get through the day. They may be
depressed, have anxiety disorder. They may, in
fact, be victims of socio-economic problems.
They may be victims of family abuse, spousal
abuse, or parental abuse. They take drugs to
just get through the day. And in many cases
they are self-medicated. But the bottom line is,
people take drugs because they like what drugs
do to their brain.
And here’s your neuro-science lesson. I am a
neuro-scientist and I couldn’t leave you today
without a little bit of the neuro-science of what
we’ve learned in the last five or ten years. And
this is, and if I had my pointer, I could show you
that this is the reward pathway for the brain, or
the pleasure centers in the brain if you will.
What drugs and abuse do is, they hijack this.
You can see here, alcohol, cocaine, heroin, all
work in the various areas of the reward
pathway, and they work at the level of the
neuron or the brain cell itself.
This is one of the terminals of the brain cell.
They work on many neuro-transmitter systems,
seretonin, norepinephrine, gabba. But they all
seem to work. There’s some commonality there.
And they all work on the dopamine system. And
what happens here is that a nerve impulse
comes down into the neuron and it causes the
release of the dopamine. It crosses that space
there and binds to those dopamine receptors
and stimulates that next cell. You like that. And
in fact, if a lot of dopamine comes down and
stimulates that, you get a very euphoric feeling.
But Mother Nature, in her wisdom, decided
there needed to be a mechanism to turn this
system off because this is the normal way you
experience pleasure. So, there is in fact, as you
see here in the red, mechanisms that really
scoops up or transports back the dopamine back
into that cell.
That’s where drugs of abuse like cocaine work.
They block the reuptake of that dopamine.
If you measure the amount of dopamine in that
space with drugs of abuse as you can see here,
cocaine, methamphetamine, nicotine, THC, they
all cause a dramatic release of dopamine into
that space. You love that release. That’s part of
what causes this euphoric feeling or this high
associated with drugs of abuse.
But this doesn’t happen in the long-term. In
fact, long-term changes occur in the brain after
you stimulate this system over and over again.
So, we know that prolonged drug use changes
the brain in long-lasting and fundamental ways.
And it’s as if there’s a switch in the brain that
flips. Something changes. And we don’t have
very much research at this point about what
that transition is, from somebody who goes from
voluntary drug use to addiction. They’re
different states. There is something that
happens in the brain and we don’t actually know
all about it. That’s one of the areas of research
for the future.
But here’s an example of that change. Those
long-lasting and fundamental changes that
occur in the brain. As Dr. Clark pointed out,
methamphetamine is a very big problem in
many countries, many communities around the
United States.
This is the front of the brain. The top is the front
of the brain. The back of the brain, the left and
the right. The area there is the striadum. And
what that is showing you is that dopamine
transporter or that scooper molecule, and the
first one is a control. The second one is a
methamphetamine addict three years after his
last methamphetamine. Three years. There’s a
dramatic reduction in the amount of that
molecule that’s in this individual’s brain, in his
striadum.
Methadone addict. Same thing. Three years
after his last drug. And the last panel is for
comparison, is a Parkinson’s Disease patient
who has a dramatic deficit in the dopamine
system in his brain.
People often ask me what that means. And this
is very new data that just came out. Again, top
is normal controls. The bottom is individuals
and there are about 13 people in this study.
Individuals who are chronic methamphetamine
abusers. And you can see on the bottom a
dramatic reduction in the amount of dopamine.
This is actually dopamine transporter in
methamphetamine abusers as it was in the last
slide. But what does that mean? Well, they
tested the meth abusers compared to the
controls and this is the first time there have
been data on the functionality changes
associated with those long-term changes in the
brain. They found two simple things: motor
tasks and memory tasks. It took longer for them
to walk from here to there for the
methamphetamine addicts. And their memory
was not as good in terms of a word recall. So,
they’ve got cognitive problems and they’ve got
some motor problems associated with that long-term
change in the brain.
So, as they say then, addiction results from
long-term effects of drugs on the brain. And the
brains of addicts are different from the brains of
non-addicts. And those differences are really the
essential element of addiction. So addiction is
fundamentally a brain disease, but it’s not just a
brain disease. That would be a little bit easier
for the scientists to discover how to fix that. It’s
in fact, the quintessential bio-behavioral
disorder. What I mean by that is in fact that the
biology, the behavior and the social context all
become intertwined in this disease. And if, in
fact, you go to make some progress in treating
people with addiction, you need to attend to all
of those things. It’s as if the challenge for
treatment is to flip the switch back in the brain
by behavioral therapy, counseling, medications,
job placement, a number of different things
from biology, behavior and social context. The
most effective treatments will, in fact, attend to
all of these. And we have a number of things in
our clinical toolbox that can help us do those
things. These are just some therapy manuals
that the Institute published last year. One on
cognitive behavioral approaches and one on
community reinforcement. You can order those
at the NIDA exhibit. And there’s also, of course,
a number of medications, as Dr. Clark said.
Methadone, nicotine replacement, are coming
on line in the coming year and we hope
buprenorphine.
Dr. Clark did a really eloquent and
comprehensive job of listing a lot of the
principles of effective treatment that we
published in the NIDA Principles of Drug
Addiction Treatment last year.
So, as I said, the most effective treatment
strategies will in fact attend to all those things.
Treatment, pharmacology, or counseling are
very important but they’re not the only things
that have to be part of the comprehensive
successful and effective treatment program.
There needs to be childcare services and
vocational services as well as a whole host of
other things.
And as we have a variety of effective treatment
options in the toolbox, we need to do better. In
fact this is just a list to show you what’s in the
pipeline for the future. We have a whole host of
behavioral therapies that are in various stages of
research that we hope will be available in the
clinic and in the community in the not-too-distant
future. So too do we have a host of
medications as anti-cocaine agents that are in
various stages of development. This is all part of
NIDA’s Future Treatment initiative to move
treatment from the lab into the community, into
real life settings for new treatment components
as well as improvement of existing treatment
components.
One of the ways we’re doing that is we’ve
launched the clinical trial network; the National
Drug Abuse Clinical Trial Network will test
effectiveness in real life settings, behavioral and
medication treatment. We envision there will be
nodes of research, regional research training
centers, partnered with community treatment
programs. Five to ten community treatment
programs that will test various therapies—behavioral, pharmacological, in various real life
settings with diverse populations, as Dr. Clark
said. And in fact, we’ve established the first six
of these through NIDA grandiosity. So, we
envision this to be a national program in the
next few years. We’ve made the first six awards.
We’re going to make another six awards this
coming year. And in the following year we hope
to make an additional five or six. So, with a
national clinical trial network, not only to test
therapies in real life settings and to get them
incorporated into the community treatment
programs, but also to use it as a vehicle to
disseminate other areas of research, whether it
be neuro-science or genetics. Science is
available to replace ideology at the local and
community level as well as the national level.
Thank you.
Click to see the slide presentation.
