Addiction - Biological - Genes Flashcards
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 gambling 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 DRD2 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 explaining why some people engage with addiction.
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 had a 35% concordance rate while DZ twins had a 0% concordance rate for drug dependency.
Name one 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.
This is also more ethical as it reduces the amount of blame placed on the addict themselves by taking a deterministic view and suggesting that their addiction could not be controlled.
However this could lead to individuals seeing their addictions as unchangeable and as such making not effort to aid their own recovery and taking no responsibility.
Name one strengths of the genetic explanation of addiction
Another strength of the genetic explanation of addiction is that it has research evidence to support its role in addiction. We can use twin studies to observe the role of genetics through the difference in concordance rate between DZ twins of 50% genetic similarity and MZ twins of 100% genetic similarity.
An example of one such twin study is Kendler and Prescot who studied 2000 females cocaine dependency among DZ and MZ twins. Finding a 0% concordance rate between DZ twins but a 35% concordance rate between MZ twins. Showing that the role of genetics may potentially play a bigger role than environment in addiction.
Name one 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.
Name another weakness of the genetic explanation of addiction (WIP)
A second weakness of the genetic explanation of addiction is that it ignores the role of alternative factors. Kenneth and Kendler showed that the heritability of tobacco use changed over time by studying swedish twin pairs born between 1910 and 1958 they found that in women born in the earlier years, there was very little influence of genetic facotes yet those born in the later years they had a 60% heritability rate.
The genes explanation does not account for these nuancies as is therefore a weakness of this explanation.
