Neurochemical Explanation for Nicotine Addiction

• Dopamine is a neurotransmitter that has an excitatory effect on neurone, creating a feeling of pleasure
• Initiation of Nicotine Addiction:

  1. Nicotine takes over pleasure + reward pathways in MSL
  2. VTA contains mainly dopamine neurons that stimulate the release of dopamine into the NAcc (pleasure centre)
  3. This affects the PFC - responsible for decision making

  Explaining why smokers choose short term rewards despite long term losses. Nicotine over stimulates dopamine pathways causing pleasure
• Maintenance of Addiction:

  1. when someone is without nicotine it is metabolised
  2. smokers experience acute withdrawal symptoms because the nicotinic receptors are available but not stimulated (sensitised)
  3. to avoid withdrawal, individual smokes, activating the nicotinic receptors
  4. continuous cycle of activating nicotinic receptors and deactivating receptors (sleeping) causes receptors to be permanently desensitised (chronic desensitisation)
  5. smoker increases nicotine intake for the same effect - tolerance
• chronic desensitisation means some of the nicotinic receptors will be permanently unavailable because of overstimulation from frequent nicotine use
• Evaluation for brain neurochemistry - addiction:

  (P) supporting research evidence

  (E) McEvoy et al (1995)

  (E) studied smoking behaviours in schizophrenics taking haloperidol (reduces dopamine) and found an increase in smoking. It was used as self medication by increasing dopamine release

  (L) this reinforces the importance of the dopamine reward system in nicotine addiction
• Evaluation for brain neurochemistry - addiction:

  (P) real life practical applications

  (E) when a theory has real world applications, effective treatment

  (E) Nicotine Replacement Therapy (patches, inhalers) has been developed to help overcome addiction. NRT gives a controlled amount of nicotine allowing them to manage their withdrawal activating dopamine reward pathways

  (L) suggesting neurochemical explanation of nicotine addiction has developed successful treatments, increasing validity.