The Neurobiology of Addiction
Physical
vs.

Physical addiction
actually changes
structure of brain

Brain needs drug for
“normal” function

Permanent brain
damage can occur

Can begin after 1st use
Psychological

Users think they
need it, but no true
chemical need

Bad habit, socially
reinforced
(marijuana, caffeine)
Inside the brain:

Brian cells called
neurons send chemical
messages

Neurotransmitter chemical messenger

Synapse - Space
between neurons where
neurotransmitters travel
The Brain’s reward center

Reward center is
region of brain that
responds to
sensations of
pleasure
 Dopamine naturally
stimulates the
reward center
 Many drugs
simulate this
process
When things are going well…

Neurotransmitter
Dopamine is released,
carries message, then
re-enters original
neuron for reuse

Responsible for feelings
of pleasure

Designed to reinforce
positive behavior
(eating, sex, altruism,
learning)
When cocaine is present

Cocaine blocks the
reuptake of
dopamine

Synapse is flooded
with dopamine,
causing feeling of
euphoria
Long-term Damage?




Long-term drug use
results in loss of
dopamine receptors
Users report constant
depression, sadness,
feelings of
hopelessness
Need more and more of
the drug just to feel
normal
Potential for “high” is
gone
Meth Brain Damage
Meth Brain Damage

The limbic region,
involved in drug
craving, reward, mood
and emotion, lost 11
percent of its tissue.
"The cells are dead and
gone," Dr. Thompson
said. Addicts were
depressed, anxious and
unable to concentrate.

The brain's center for
making new memories,
the hippocampus, lost 8
percent of its tissue,
comparable to the brain
deficits in early
Alzheimer's. The
methamphetamine
addicts fared
significantly worse on
memory tests than
healthy people the
same age.
The faces of Meth
And finally…Meth Mouth

Meth users feel
incredibly sexy
because of the high

They actually
deteriorate very
quickly due to their
fixation on the drug
and its harmful
effects