Brain neurochemistry

• >Brain neurochemistry is an explanation for nicotine addiction

  > States that a nicotine addiction is formed by repeated activation of reward pathways
• part 1 -

  > nicotine is inhaled and reaches nicotine receptors in the brain in less then 10 seconds

  > triggers neurons in the ventral tegmental area (VTA) to release dopamine

  > travels down a reward pathway called mesolimbic pathway

  > dopamine stimulates D2 receptors in the nucleus accumbens - pleasure/ euphoria - motivated person to smoke again starting the addictive behaviour
• part 2 -

  > dopamine also travels down mesocortical pathway

  > Dopamine stimulates the pre-frontal cortex, making the person pay attention to smoking and everything associated with it, make decision to smoke again
• Upregulation

  > when a person hasn’t smoked for a period of time, the nicotine receptors become available - withdrawal

  > increase in numbers of nicotine receptors so more nicotine is needed to feel the same effect
• Downregulation

  > D2 receptors in nucleus accumbens become less sensitive and reduce in number, dont feel the same buzz from smoking - more nicotine needed to feel the same buzz - tolerance
• AO3 -

  :) RTS McEvoy - dopamine antagonists

  COUNTER sample bias

  :( Biological reductionism

  :) Practical applications
• Brain neurochem AO3

  :) RTS McEvoy

  > They studied smoking behaviour in people with schizophrenia who were taking a drug (Haloperidol).

  > This drug is a dopamine antagonist by blocking dopamine receptors - lowering the level of dopamine activity in the brain

  > It was found that the people taking the drug showed a significant increase in smoking

  > Therefore, supporting the role of dopamine as an explanation of addiction to nicotine, as the patients sought nicotine to increase their level of dopamine in the brain and experience euphoria.
• Brain neurochem AO3

  :( Biological reductionism

  > Theory reduces the complex human behaviour of nicotine addiction down to dopamine levels in the brain

  > This neglects a holistic approach, which takes into account how a persons social and cultural context would influence and explain an individuals nicotine addiction

  > Therefore the brain neurochemical explanation may lack validity
• Brain neurochem AO3

  :) Practical applications

  > Nicotine addiction is caused by dopamine and increased numbers of nicotine receptors has led to the treatment of nicotine replacement therapy (NRT)

  > This provides the individual with nicotine in a less harmful form (patches) and reduces dosage overtime, thus reducing tolerance and dependence as the individual’s nicotine receptors return to normal levels.

  > Therefore, the brain neurochemistry explanation of nicotine addiction is an important part of applied psychology when helping to treat nicotine addiction in the real world.