Nicotine Addiction: GENETICS Flashcards
Brain Chemistry and Dopamine
(Essay Only) How does the behaviour of Smoking initiate according to the function of genes? (3 points)
- Some people inherit a genetic vulnerability to start smoking & ultimately develop an addiction
- One candidate gene for smoking is the A1DRD2 variation
- Seems to cause defective & insufficient dopamine receptors in the brain’s reward circuitry, meaning individuals can’t produce pleasure naturally & may engage in smoking behaviours to raise dopamine to optimal levels
How is Smoking maintained - IN SHORT (2 points)
- As nicotine is a stimulant it increases the production & activity of dopamine in the brain
- We tend to find this very rewarding, which leads to repetition of the behaviour
How is Smoking maintained according to dopamine activity (5 points)
1 - Nicotine stimulates specific receptors - acetylcholine receptors (NaCR)
2 - This causes rise in dopamine activity in the VTA : critical area in the brain’s reward circuitry highly populated with NaCR = rewarding sensation
3 - VTA activity caused by nicotine is then projected to the nucleas accumbens = producer of dopamine located deep in the mesolimbic dopamine pathway
4 - Nucleas accumbens = priamry reward centre in the brain, and as dopamine use rises, users evaluate it as very pleasurable - compelling more use
5 - (ADDITIONAL HIT) At the same time, the nucleas accumbens encouraged to release more dopamine as nicotine stimulates endorphins that reduce GABA - correlated with further rises in dopamine
How do Smokers relapse according to the process of downregulation (4 points)
- Nicotine triggers dopamine firing in the mesolimbic pathway = a reward or a ‘kick’
- With LT use, the Nicotine Regulation Model suggests the smokers ‘reward system’ becomes less active (downregulation) i.e. specific acetylcholine receptors become inacitve = anxiety
- To avoid this, smokers continue to maintain certain level of nicotine in their bodies to avoid unpleasant side effects
- As a result of this, an increased amount of nicotine is needed to achieve the same initial ‘kick’
(Strength) Outline Paterson et al’s (2002) study (3 points)
- Researched the use of Gamma-vinyl GABA, which **redueces the surge of dopamine in the nucleas accumbens
- Effectively reduces addictive properties of nicotine, without major side effects
- Illustrates the involvement of dopamine with smoking addiction
(Strength) What is the Practical Application of the biochemical explanation? (2 points)
- Delivering therapeutic doses of nicotine in the early stages of smoking
- The use of inhalers has been shown to keep 28% of the treatment group off smoking for 12 months
(Weakness) Outline Nerin & Jane’s (2007) study (3 points)
- Showed ‘Beta bias’
- Argued onset of smoking addiction has significantly different between sexes i.e. women typically start smoking much later
- The biological reasoning for this is ignored
(Weakness) Explain how the account neglects the role of NURTURE (2 points)
- Peer approval for smoking can create reinforcement (that activates dopamine) - little to do with the biological action of nicotine
- Perhaps nicotine & peer approval collectively account for rises in dopamine