Transcript 108721_Drug_Notes.ppt

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,
though often requires
repeated use
Psychological

Users think they
need it, but no true
chemical need

Bad habit, socially
reinforced
(marijuana, caffeine)
Inside the brain:

Brain 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 (one
of multiple such
neurotransmitters)
 Many drugs
simulate this
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