Biolgical Explantions - Addiction Flashcards
Biological explanation 1 - Dopamine (10 marks)
Brief intro - can be explained by the role of dopamine in brain - typically increased in addicts
P1 - mesolimblic system:
Known as reward pathway
Pleasurable feelings will reinforce behaviour
Some behaviour make biological sense to repeat e.g eating but typically drugs activate reward centre
VTA - produces dopamine and travels to NAC which receives dopamine and feels a jolt of pleasure
Research shows that alcohol increases dopamine in the brain
P2- tolerance and withdrawal:
Brain adapts with experience and strives for equilibrium
If a drug is consumed regularly we upset the balance so it regulates
We then may experience withdrawal as we have to adapt to the absence - no longer take for pleasure but to avoid withdrawal symptoms
When a drug is taken repeatedly the effects will be diminished = tolerance
Different receptors are compatible with different neurotransmitters e.g D2=dopamine - the brain can reduce receptors which increases tolerance
Vesicles (sacs containing NT (dopamine) are released to the synapses which binds to d2
-research shows that users of cocain = decrease in d2 and release of dopamine
P3- maintaining addiction:role of frontal cortex:
Frontal cortex is implicated in the maintenance of addiction
Mesolimbic system impacts the frontal cortex which is responsible for things such as impulse control, decision making, and judgement
When the drug is no longer being taken and the negative withdrawals and tolerance have disappeared relapse still likely to occur due to damaged impulse control
Research shows - although the dopamine reward pathway = starting point for addiction, it is the changes/damage to frontal lobe that turn engaging in the behaviour an addiction
Cortex is responsible for high levels of thinking so more likely to relapse as tuneup hgh higher activity when re exposed to drug
Evaluation of biological explanation - dopamine doesn’t increase for all addictions
S- limitations - not all addictive behaviours increase dopamine levels
E-the theory hypothesises that dopamine increase is involved in both the creation and maintenance of addiction however some addiction shows no changes in dopamine levels
E- e.g research found no significant increase in dopamine levels in volunteers taking cannabis or taking alcohol
W-Therefore, it may not be appropriate to say that dopamine explains all addictions
Evaluation of dopamine - dopamine does not perform just 1 function
S-limitation
E- refers to dopamine as the ‘Kim Kardashian of neurotransmitters’ suggesting it has become fashionable to blame dopamine for a range of issues
E-isn’t just linked to pleasure e.g research shows an increase in war veterans suffering with ptsd when reminded of battle through combat sounds
E-limitation as is does not match the idea that this area of the brain is simply about pleasure and experience therefore less suitable in explaining addiction
Ethical evaluation of dopamine
S- weakness as many studies utilise animals
E-does not give true insight into how humans become addicted and also misses the social context so can’t replicate behavioural addictions like gambling
C- however can study the effects of drugs not possible in humans e.g making rats self stimulate to the point of overdose
W- can be helpful in studying some addiction but major ethical issues and cannot be extrapolate to humans
Evaluation of dopamine - reductionist
S- weakness
E-there are many factors that are ignored
E-ignores any environmental factors e.g relationships or trauma - if it was purely biological then everyone would be an addict
W- dopamine alone is not a sufficient explanation furthermore dopamine can’t explain how/why addiction starts
biological explanation - genes
p1- two genes that are identified as addiction genes
DRD2:
is a dopamine gene that codes for the amount of dopamine receptor sites - if they have the A1 mutation it means they have less D2 receptor sites this results in less pleasure as dopamine floods but has no where to bind to causing them to overcompensate (addiction)
-comings et al- found that 48.7% of smokers/ex smokers carried the A1 variant of DRD2 compared to 35.9% of population
p2- ADH:
adh/aldh breaks down alcohol and is responsible for how it is metabolized
those at risk to alcoholism have a mutation causing adh to break down quickly then aldh to break down slowly whereas those less at risk go slow then quick - this is supported by alcohol rates in east Asian countries as it causes unpleasant stimulus e.g nausea so they don’t want to drink
p3- diathesis stress model:
genetic predisposition makes people venerable to addiction but it needs to be triggered by a life stressor to cause addiction
e.g a person with just life stressor is less likely to become an alcoholic than someone with genetic vulnerability + stressor
Genes - point for a plural question
Genes associated with addiction:
DRD2 is a dopamine gene - individuals with the A1 variant have fewer D2 receptors
This impacts behaviour as we experience less pleasure as dopamine floods the synapse but has no where to bind to causing them to overcompensate (addiction)
Comings et al found 48.7% of smokers and ex smokers carried the A1 variation compared to 25.9% of the general population
Another gene is ADH - this protects you from alcoholism
ADH breaks down quickly then ALDH breaks down slowly meaning you experience negative effects of alcohol which will deter you - this is the case in East Asian populations
Genes - evaluation point
S- key strength of genetic explanation as its deterministic so can explain why some people are more likely to become addicted to
E-if we can say addiction is determined by genes we can research more into biology/genes which can help us top develop treatments
E-the ‘disease model’ suggests addiction should be treated as an illness so removes society’s stigma
C- however deterministic = removes responsibility and less accountable for actions linked to their addiction- it could also make the individual feel helpless as they can’t ’change’ their genes
W- is helpful as it states genes = addiction allowing us to find helpful treatments but it can be damaging as there are other factors that contribute to addiction e.g social environment which is free will
