980641
Biological Model of Addiction
- Outline
- physical cause for addiction
- physiological aspects of addition
- which changes are
occurring in the brain
- physiological aspects of addition
- Dopamine Pathway
- Mesocorticolimbic Dopamine Pathway (MDP)
- "pleasure centre"
- concerned with pleasure & reinforcement
- eating, drinking & sex - stimulate this area of the brain
- why these are activities reengage in repeatedly
- drugs can also stimulate this
area e.g. smoking
- why these are activities reengage in repeatedly
- nicotine - produces this reward in the brain
- stimulates the release of Dopamine
- why dopamine = pleasurable
- only small amounts of nicotine is needed to stimulate
MDP - why nicotine is so addictive
- why dopamine = pleasurable
- "pleasure centre"
- Mesocorticolimbic Dopamine Pathway (MDP)
- Wise
- individual differences in addiction may, in
part, be due to the individual differences in
neural circuitry in the brain
- brain structures differ
- dopaminergic system - more active = more dop released
- brain structures differ
- individual differences in addiction may, in
part, be due to the individual differences in
neural circuitry in the brain
- good for smoking not for gambling as much
- :( reductionist - doesn't consider social or psychological factors
- physical cause for addiction
- Initiation
- Genetic factors
- risk-taking gene
- DRD4 (Dopamine Receptor D4) gene
- if a person has this mutation - they'll
will do riskier things
- :( just engaging in riskier activities doesn't mean
beginning an addiction
- any adrenaline-fuelled pass time could be
initiated e.g. extreme sports
- any adrenaline-fuelled pass time could be
initiated e.g. extreme sports
- DRD4 (Dopamine Receptor D4) gene
- risk-taking gene
- CYP2A6
- gene responsible for ridding the body of nicotine
- 1 reason why nicotine wears off quickly
- i.e - fully functioning copy of this gene = not beneficial
- breaks down nico very quickly - want another one sooner
- breaks down nico very quickly - want another one sooner
- 1 reason why nicotine wears off quickly
- defective copies - break down nicotine
more slowly than others
- less likely to become addicted to nicotine = beneficial
- less likely to become addicted to nicotine = beneficial
- gene responsible for ridding the body of nicotine
- Genetic factors
- Maintenance
- dopamine releases by brain only lasts a fairly short time
- why another cigarette is needed
- so more dopamine can be
released & smoke can feel
pleasure
- Desensitisation
- person smoke frequently
- consequence of stimulating the
brain for prolonged periods
- brain stops it from being so sensitive to
nicotine to protect itself from producing excess
Dopamine
- needs more to produce same pleasure = tolerant
- postsynaptic = loses sensitivity
- more nicotine to create more dopamine & maintain
their "high"
- more nicotine to create more dopamine & maintain
their "high"
- needs more to produce same pleasure = tolerant
- person smoke frequently
- so more dopamine can be
released & smoke can feel
pleasure
- why another cigarette is needed
- prefrontal cortex (PFC)
- loses activity as well
- can't prevent the person from indulging in
behaviours they might otherwise suppress
- e.g. take another cigarette
- e.g. take another cigarette
- can't prevent the person from indulging in
behaviours they might otherwise suppress
- suppresses inappropriate responses
- loses activity as well
- dopamine releases by brain only lasts a fairly short time
- Relapse
- Wise
- same neural circuitry is activated by opiates,
cocaine, alcohol, nicotine & caffeine
- may explain: why use of one of the above can
trigger relapse of another
- activate the relapse of another drug
- activate the relapse of another drug
- may explain: why use of one of the above can
trigger relapse of another
- same neural circuitry is activated by opiates,
cocaine, alcohol, nicotine & caffeine
- Wise
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