Biological Explanation For Addictive Behaviour Flashcards
Addiction genes
S- One biological explanation of addictive behaviours is addiction genes. This is the idea that addiction is passed down through genes from one generation to another.
E- one way which this was study was through the inheritance studies for example Prescott and Kendler found that monozygous twins had a much higher concordance rate compared to dizygous twins suggesting that the more gene shared the higher likelihood of addiction.
Furthermore kendler also found the individuals who have half or four parents or siblings who were drug addicts and they were much more more likely to be a drug addict themselves.
Furthermore, there are two important genes which are linked to alcohol addiction: ADH and ALDH.
Normally when someone consumes alcohol is broken down by the ADH enzyme into acetaldehyde and then acetaldehyde is broken down into acetate by an enzyme coded for ALDH.
Genetics
One biological explanation of schizophrenia (SZ) is genetics. This explanation believes that SZ is inherited through genes that are passed down through families.
E - For example, Gottesman investigated the herability of SZ and found that parents and siblings have a lower risk of developing SZ because the genetics is not 100% compared with MZ twins ( but still has a higher concordance rate than more distant relatives)
C- however it did not imply that more closely related you are to someone who is diagnosed with SZ, the higher the concordance rates which suggests that SZ is a highly genetic disorder
Futhermore, twins studies found concordance rates of 42% for identical twins and 9% concordance rates in fraternal Twins .
- this suggests that identical twins could share a genetic component that could be responsible for SZ however due to the statistics not being fully 100% there are other factors that play a role in the development of SZ such as cognitive factors.
Additionally, adoption studies have also been done to understand the role of genetics in SZ development.
E- for example, Heston compared 47 children with SZ mothers who were adopted before the age of one month compared to with a control group of 47 children raised by their non SZ adopted mothers.
-furthermore, 10% had SZ mothers developed it themselves whereas non of the other children did.
E- this suggests that there is a genetic component even in a non SZ environment, however it’s not due to biology alone
W- there are other environmental factors that need to be taken into account otherwise there would be a higher percentage of the children with SZ mothers that would have developed the condition
Lastly candidate genes or faulty genes can be used to explain the development of SZ
E- for example research found that SZ is polygenic which means that many genes contribute to SZ.
- Furthermore different studies have identified that different candidate genes means that several genes work together
E- this suggested that these genes that were identified included those that code for the transmission of different neurotransmitters including dopamine.
Additionally, researchers have have recently identified a gene that they believe increases the risk of schizophrenia called the C4 gene which appears to be involved in eliminating the connections between neurones and it is possible that excessive inappropriate pruning of neural connections lead to the development of schizophrenia which is symptoms such as disordered thinking .
Evaluation of genetics - para 1- strength
S- One strength of the biological explanation of genetics is that there is supporting research to for the genetic vulnerability of SZ as numerous twin studies have shown a genetic link to the disorder.
E- For example, a research investigated family studies and found that that parents and siblings have a lower risk of developing SZ because the genetics is not 100% compared with MZ twins.
E- However it did imply that the more closely related you are to someone who is diagnosed with SZ, the higher the concordance rates which suggests that sZis a highly genetic disorder and twin studies found concorclance rates of 42% for MZ twins and 9% concordance rates in DZ twins.
W- This is a strength because it supports the genetic explanation as MZ twins share more genes with each other 100% than DZ twins 50% and if SZ is caused by a genetic factor then you could expect higher concordance rates for MZ twins than DZ twins which it is.
- However because the Concordance rates are not 100% there could be other factors that need to be taken into account.
Evaluation of genetics para 2
S- One way to overcome this issue of twins sharing the same environment, is to look at adoption studies.
E- For example, one study compared 47 children with SZ mothers who were adopted before the age of one month compared to with a control group of 47 children raised by their non - SZ adopted mothers. 10% who had SZ mothers developed it themselves whereas non of the other children did. W- This is a strength because it is useful as it establishes the difference between nature and nurture and it shows that although the twins did not share the same environment and parenting there is still a biulogical genetic component that can be responsible for the development of SZ because their mothers had been previously diagnosed with it.
C- However There are other environmental factors
that need to be taken into account otherwise there would be a higher percentage of the children with SZ mothers that would have developed the condition as 10% is still relatively low- which shows a genetic basis
Evaluation of genetics para 3
S- One strength of the genetic explanation is that newer technology can be used to identify certain genetic mutations that may lead to the development of SZ.
E- Newer studies use gene mapping technology and have identified specific genes that could increase the risk of SZ developing such as the SETD1A gene. Mutated genes such as this can increase the likelihood of developing SZ by 35x although rare and this gene is only found in SZ patients.
E- This is a strength because this can enable interventions such as genetic counselling and inform people about their genetic makeup
C- however it can raise ethical issues such as eugenics.
W- The biological explanation is a strength because it has supporting evidence both in twin studies and adoption studies which
highlights that there is a genetic component in the development of SZ however these studies are not 100% which shows that there are other factors that should also be taken into account however it can enable
Interventions such as genetic counselling to be introduced to help make decisions about having children and the impacts.
