Addiction - biological Flashcards
What are the two biological explanations of addiction
Genes
Dopamine
What is an advantage over using Genes instead of Dopamine to explain addiction
An issue with the dopamine explanation is that is does not explain individual differences in addiction. Like how many people can engage with addictive behaviours like video games or alcohol and not become addicted and other become extremely addicted and it consumes their life.
However, a genetic explanation does help explain this – Goldman et al said ‘addictions are moderately to highly heritable’
What are the two genes involved in addiction?
DRD2 and ADH
How does the D2 gene cause addiction?
The D2 dopamine receptor gene has been linked with addictive behaviours.
While we all have DRD2 genes, some of a variant named the A1 variant of the DRD2 gene have found to have less dopamine receptors in the brain than the average person, the lack of receptors means it’s harder for them to get pleasure out of ordinary things than the average person. This is why they engage in addictive behaviours to try and compensate with this lack of dopamine by overstimulating themselves with these addictive behaviours.
What KEY STUDY supports the D2 gene causing addiction
Key Study: Comings et al (1996) found that that despite just 26% of the general population having the A1 variant of DRD2, 49% of ex -smokers carried this gene and 51% of gambling addicts.
How does the ADH gene cause addiction?
ADH is a gene that is responsible for the ADH enzyme, this enzyme is used to break down alcohol.
Depending on the different variant of ADH, it will give you more or less of a severe reaction to digesting alcohol depending on the amount of ADH enzyme produced (more enzyme = metabolized / broken down faster therefore more severe reaction).
It is thought that those with a less severe reaction are more prone to getting addicted as they must drink more to experience the same effects.
This is supported by the fact it has been found in east-Asian countries they have a faster metabolism variant of ADH and therefore there is less of a drinking culture there compared to other countries.
What KEY STUDY supports the ADH gene causing addiction
Key Study: Kendler and Prescot (1998) Twin study conducted on 2,000 female twins. Found that genetics played a bigger role than environment when determining addiction to drugs.
Results found that MZ twins (100% shared DNA) had a 35% concordance rate while DZ (50% DNA) twins had a 0% concordance rate for drug dependency.
Name two strengths of the genetic explanation of addiction
A strength of biological explanations such as genes at explaining addiction is that it is deterministic, this is because this explanation accounts for individual differences for addiction such as why some people can engage in addictive behaviours and not become addicted while others do become addicted.
Another strength is that it is a more ethical explanation as it reduces patient blame for their addiction. Although it could be argued this view will not benefit the patient as they may then take less responsibility for their recovery as they see their addiction as an unstoppable reality decided by their genetics.
Lewis (2015)
Argues that labelling addiction as a disease damages the self-esteem of an addict as it makes them feel helpless. (Add link to method of modification at some point)
It could also lead to the addict being less likely to accept responsibility which is important if they are to overcome their addiction.
What does the dopamine explanation suggest about addiction
A common assumption about those with addictions is that it is a choice, aka a lack of willpower that leads them to become addicted.
However, this explanation suggests there are biological elements that contribute to addiction – such as the role of the neurotransmitter dopamine.
Dopamine is involved in all four stages of addiction Initiation
Name a weakness of the genetic explanation of addiction
One weakness of using genes to explain addiction is that it could be argued it is simply reductionist to claim that an addiction is caused solely by genes when there is so many different genes involved at different stages of the process. A diathesis stress explanation may be deemed as more effective way of explaining addiction considering it accounts for both nature and nurture. This model suggests that a disorder such as addiction only develops when a genetic predisposition is triggered by an environmental stressor.
Evidence for this is Kaudman et al who found the gene 5HTT to be both linked with alcoholism as well as maltreatment in childhood.
(need to add second weakness if there is one)
What are the four stages of addiction?
Initiation, Tolerance, Maintenance and Relapse
How does dopamine link to Initiation
Addictive behaviours activate the mesolimbic pathway in the brain (known as the reward pathway)
The addictive behaviour triggers the release of dopamine in the ventral tegmental area of the brain leading to a sense of pleasure in the nucleus accumbens.
Humans have evolved to feel pleasure when we engage in adaptive behaviour like eating and drinking as we need it to live! However, some non-adaptive behaviours also release huge amounts of dopamine making an individual want to repeat the behaviour which leads to a maladaptive reward pathway system.
How does dopamine link to Tolerance
Tolerance refers to how repeated exposure to something results in reduced sensitivity to the dopamine release as the dopamine receptors become gradually less sensitive to the effects of the substance / behaviour – this means more of the behaviour is needed to feel the same pleasurable effects in the mesolimbic system.
Volkow (1997) found those with a cocaine addiction had a decrease in D2 receptors and dopamine release than those without a cocaine addiction
How does dopamine link to Maintenance
Volkow suggests that although the dopamine reward pathway is what causes an addiction to begin. An addiction is maintained because of changes in the frontal cortex.
Meaning the addictive behaviours changes the brain circuits that decide what the individual should pay attention to causing the addictive behaviour to become the focus of the individual’s life.
This explains why many addictions don’t even enjoy the addiction but engage anyway, as they get dopamine from craving the addictive behaviour rather than engaging with it
How does dopamine link to Relapse
This change in brain circuits can also be used to explain why addicts relapse,
The brain-circuit changes lead to lasting memories of the addiction – so when the individual gives up they may still be exposed to environmental reminders such as being in a pub / club which will release dopamine at the thought of drinking for instance. This bit of dopamine causes the addict to crave more dopamine causing them to return to addiction.
