Evaluation: Role of Dopamine

Question 1

What proof is there to show that not all addictive behaviours increase dopamine levels?

Answer 1

• There is evidence to show increased dopamine levels following consumption of some drugs.
• Cannabis + Dopamine Levels = no significant increase (Paul Stokes et al, 2009).
• Alcohol + Dopamine Levels = no consistent increase (Karmen Yoder et al, 2007).

Question 2

Why should dopamine not be used as the only explanation for addiction?
(complexity of the role of dopamine)

Answer 2

• Using as the only explanation ignores dopamine’s range of functions.
• It’s been described as the ‘Kim K of Neurotransmitters’ as it’s fashionable to blame (Vaughn Bell, 2013).

Question 3

What is the truth regarding the brain systems involved in addiction? Provide evidence/research.
(complexity of the role of dopamine)

Answer 3

• Brain systems involved are more complicated than the media presents.
• Aversive (unpleasant stimuli) also increases dopamine as the brain systems motivate us to seek something pleasant + avoid something unpleasant.
• War Veterans with PTSD = increased activation in NAc when exposed to combat sounds which doesn’t match the idea of being simply about pleasure (Israel Liberzon et al, 1999).

Question 4

Why did David Nutt et al (2015) criticise methodology of research into the role of dopamine in addiction?
(methodological issues)

Answer 4

• Samples are often small.
• Substances used to measure effects are given in different form (cig = nicotine inhilator).
• Lab instead of usual environment (smoking in groups).
• Measured effects may not be accurate.

Question 5

What are the advantages and disadvantages of non-human animal studies?

Answer 5

• Allows study in ways not possible with humans (depleting dopamine neurons to see effect of rat self-stimulating with drugs).
• May not give true insight into human addiction; misses social context and can’t replicate all addictions (gambling isn’t generalisable to humans/all types of addiction).