Biological Explanations of Schizophrenia- Genetic Inheritance Flashcards
What are some of the genes involved in schizophrenia?
- C4 gene
- Variations on chromosome 8 and 11
- TPH (more common in Chinese patients, as found by Hong et al)
How is a faulty C4 gene implicated in the development of schizophrenia?
- Greater expression of C4 in the brain is associated with an increased risk of schizophrenia
- May be linked, as studies show abnormal synaptic pruning during adolescence which may be linked to a faulty C4 gene
What is the chance of a child of 2 schizophrenic parents who share 100% genetic similarity developing schizophrenia?
(Gottesman and Shields study)
46%
What is the chance of monozygotic twins who share 100% genetic similarity developing the disorder if 1 has been diagnosed?
(Gottesman and Shields study)
48%
What is the chance of first degree relatives, such as children of a schizophrenia sufferer, who share 50% genetic similarity developing schizophrenia?
(Gottesman and Shields study)
13%
What is the chance of second degree relatives, such as grandchildren of schizophrenia sufferers, who share 25% genetic similarity developing the disorder?
(Gottesman and Shields study)
5%
What is the study by MacDonald and Schultz into the link between monozygotic twins and schizophrenia?
Suggested that if 1 twin is diagnosed with schizophrenia then the other twin is 99 times more likely to suffer from the condition
What is Tienari et al’s adoption study?
- Took place in Finland with over 164 adopted children whose biological mothers had been diagnosed with schizophrenia
- They were matched with children whose biological mothers did not suffer with schizophrenia
- The study found that 11 of the children whose biological mothers had schizophrenia had also been diagnosed with the condition compared to just 4 in the control group
If the point is:
A strength of genes as a biological explanation of schizophrenia is that there is evidence to support its theoretical foundations.
What is the evidence and link?
Evidence- Joseph found some convincing support to show how genetic similarity can increase risks of developing schizophrenia. From previous data, Joseph found a 40% concordance rate in schizophrenia for monozygotic twins and a 7% concordance rate for dizygotic twins. The higher concordance rate for monozygotic twins suggests that genes have some influence on the development of the disorder. Additionally, MacDonald and Schultz suggested that among monozygotic twins, if one twin is diagnosed with schizophrenia then the other twin is 99 times more likely to suffer from the condition.
Link- This implies that the explanation of schizophrenia is credible, as it has shown that genes are involved in the development of schizophrenia.
If the point is:
A weakness of genes as a biological explanation of schizophrenia is that the explanation is incomplete.
What is the explanation, evidence and link?
Explanation- Faulty genetics cannot be the sole cause of schizophrenia, as if this was the case monozygotic twins would have a concordance rate of 100% as they share the same genotype. As this is not the case, nurturing influences must play a role in the development of schizophrenia.
Evidence- Some environmental factors linked to schizophrenia could include drug uses and other environmental stressors.
Link- This would suggest that the explanation may not be fully reliable and credible for the development of schizophrenia.
If the point is:
A weakness of genes as a biological explanation of schizophrenia is that it can be accused of being biologically deterministic.
What is the explanation, evidence and link?
Explanation- Although psychology is seeking nomothetic laws to explain all behaviours, this theory overlooks many aspects, including free will.
Evidence- It neglects to consider the role of environmental factors as well as free will in the development and potential recovery from schizophrenia.
Link- This implies that the explanation fails to consider many aspects of the development of schizophrenia, meaning its explanation is limited.
If the point is:
A strength of genes as a biological explanation is that it promotes psychology as a scientific discipline.
What is the evidence, explanation and link?
Evidence- This is because genetics can be studied in a controlled, objective and falsifiable manner. For instance, we can gather quantifiable data when studying genetic inheritance by looking at percentage similarity or genetic information between family relations and then concordance rates for schizophrenia.
Explanation- This is important as, the more scientific the research, the more trusted the conclusions on the causes of schizophrenia are.
Link- This means that practical applications are likely to be put in place based on the conclusions and more funding is likely to be given for further research into schizophrenia.
What are the evaluation points for genes as a biological explanation of schizophrenia?
+ Evidence to support its theoretical foundations
— Explanation is incomplete
— Can be accused of being biologically deterministic
+ Promotes psychology as a scientific discipline
