Explanations for nicotine addiction

Question 1

What is the nicotine paradox?

Answer 1

The finding that nicotine has both stimulant and relaxation effects.
Smoking only appears relaxing as smokers are often in state of mild nicotine
withdrawal, so smoking allows nicotine level to return to normal.

Question 2

What role does dopamine have in the brain neurochemistry explanation?

Answer 2

Main neurotransmitter of reward system in the brain.
Gives feelings of pleasure when we engage in certain behaviours that activate this reward system.
Most drugs act upon brain’s reward system by heightening dopamine activity & tending to become addictive.

Question 3

Explain the process of absorbing nicotine into the body.

Answer 3

• Typical smoker takes in 1-2mg of nicotine per cigarette
• Nicotine absorbed through lining of mouth & nose & inhalation in lungs
• Reaches peak levels in bloodstream & brain in less than 10 seconds
• Nicotine becomes addictive as it activates areas of brain that regulate feelings of pleasure (reward pathways)

Question 4

Explain how nicotine attaches to neurons and how this leads to addiction.

Answer 4

1. Nicotine attaches to neurons in brain region - ventral tegmental area (VTA)
2. These neurons trigger release of dopamine in brain region - nucleus accumbens (NAc)
3. Nicotine also stimulates release of neurotransmitter glutamate, which triggers
   additional release of dopamine
4. This release of dopamine produces pleasure and a drive to repeat these
   behaviours (leading to addiction)

Question 5

Why do dopamine levels remain high even after direct nicotine intake ends?
(Roles of Glutamate and GABA)

Answer 5

• Glutamate speeds up neuron activity
• GABA slows down neuron activity
• Nicotine causes glutamate to speed up dopamine release, but prevents GABA from slowing it down after dopamine levels have been raised
• This results in increased dopamine & amplified rewarding properties of nicotine

Question 6

How does the unknown substance in cigarette smoke contribute to addiction?

Answer 6

• Unknown substance blocks action of enzyme monoamineoxidase (MAO)
• MAO is responsible for breaking down dopamine after it has had its effects
• Therefore, this block results in
  even higher dopamine levels, strengthening smoking habit by maintaining feelings of pleasure

Question 7

How does the short lasting effects of nicotine create a continual need to smoke?

Answer 7

• Nicotine effects disappear within a few minutes
• This creates a need to continue nicotine intake to get dopamine rush
• Continued activation of dopamine-enhancing neurons changes their sensitivity to nicotine
• Results in tolerance, dependence & ultimately addiction

Question 8

What are the 3 phases that characterise nicotine addiction according to the Learning Theory?

Answer 8

1. Initiation
2. Maintenance
3. Relapse (cue reactivity)

Question 9

Explain Initiation.

Answer 9

• Observes role models smoking
• Vicarious reinforcement - expects positive consequences from smoking
• Classical conditioning - nicotine immediately rewarding, learned quick
• Feels sudden rush (10 secs peak level) - reinforces behaviour

Question 10

Explain Maintenance.

Answer 10

• Classical conditioning - not smoking leads to irritation (negative reinforcement), smoking leads to pleasure (positive R)
• Maintain habit to avoid withdrawal

Question 11

Explain Relapse (cue reactivity).

Answer 11

• Associations made by classical conditioning
• Associate situations/places with rewarding effects of nicotine
• These become smoking-related cues
• Nicotine(UCS) causes pleasure (UCR), situations(NS) become CS through repeated pairings