OCR Psychology A Level Book 2 sample

Conclusions The study showed that if both parents have a serious mental illness this significantly increases the risk of their child developing not just that particular disorder, but other disorders. Having one parent with the disorder increases risk compared with the general population but having two parents creates an even greater risk (Gottesman called this ‘a super- high-risk sample’ which would be useful for future genome studies). These results provide support for the genetic explanation of mental illness because of the increased chances of developing a serious mental illness if direct relatives have that or another serious illness. This also provides evidence for the genetic overlap between schizophrenia and bipolar disorder because if the heritability of one disorder increased, it also increased for other disorders suggesting a shared genetic factor. However, this relationship is by no means 100%, which indicates that other factors are important in the aetiology (explaining the cause) of schizophrenia and bipolar disorder. The results of this study may be useful for genetic counsellors to help inform the decisions people have to make in terms of choosing a partner, having children, and even for future legalities like adoption and health insurance. However, Gottesman warns of the misuse of data from this research, for example that it should not be regarded as evidence for the use of eugenics . Table 1 shows the percentage chance of a child developing a disorder. Any disorder Schizophrenia or bipolar disorder 2 parents with schizophrenia 2 parents with bipolar disorder 67.5% 44.2% 27.3% 24.95% 1 parent with schizophrenia 1 parent with bipolar disorder no reported results 7% 4.4% No parents with a disorder 11.9% 0.86% schizophrenia 0.48% bipolar disorder General population (will include some who have parents with a disorder) 14.1% 1.12% schizophrenia 0.63% bipolar disorder Table 2 shows the increased risk of getting a disorder if parents have the same or a different disorder. Schizophrenia Bipolar disorder Increased risk if two parents have the disorder compared with having no parents with the disorder 31.7 × 51.9 × Increased risk if two parents have the disorder compared with having one parent with the disorder 3.9 × 5.7 × Increased risk if one parent has the disorder compared with having no parents with the disorder 8.2 × 9.2 × Graph 1 shows the cumulative incidences of diagnoses of schizophrenia among people with neither, one or both parents diagnosed with schizophrenia. Results Children and parents with same or different disorder Table 1 shows that having one parent with a disorder increases the likelihood of their offspring being diagnosed with that or any other disorder. For example, a child with one parent with schizophrenia has a 7% risk of diagnosis of schizophrenia, compared with a 1.12% risk of diagnosis of schizophrenia for the general population. This increase is even more marked when both parents have the disorder. For example, if both parents have schizophrenia this increases their child’s chances of getting schizophrenia to 27.3% and even higher for a schizophrenia-related disorder. Their chances of being diagnosed with any disorder was 67.5%. Increased risk of developing a disorder Table 2 shows that children have an increased risk of being diagnosed with a disorder if their parents have a disorder. For example, the chances of developing bipolar disorder are 51.9 times higher if an individual has two parents with bipolar disorder than with no parents being diagnosed with it. This shows that having two parents with a disorder significantly increases the child’s risk of being diagnosed with that disorder. This indicates that the risk of developing a serious mental illness increases with each parent having the disorder, as the risk of being diagnosed with bipolar disorder is only 9.2 times higher if only one parent has bipolar disorder. Other results After the age of 45 there were only a few new diagnoses of schizophrenia, which suggests that the onset of schizophrenia generally occurs before 45 years of age, as shown in Graph 1. After the age of 45 years there were still new diagnoses of bipolar disorder (not shown on this graph), which suggests the risk of developing bipolar disorder does not stop at 45 years of age. Of course the study only lasted until 52 years of age so there is no evidence of what happens with diagnoses after that point in life. Those offspring that have one parent with schizophrenia and one parent with bipolar disorder had a 15.6% chance of developing schizophrenia and an 11.7% chance of developing bipolar disorder. This is significantly higher than just having one parent with either of those disorders. 40- 35- 30- 25- 20- 15- 10- 5- 0- 10 15 20 25 30 35 40 45 50 55 Age at follow-up, years Cumulative incidence, % Both parents admitted with schizophrenia Schizophrenia/schizophrenia-like disorder in offspring with both parents admitted with schizophrenia Only 1 parent admitted with schizophrenia Neither parent ever psychiatrically admitted check your understanding 1. Why did Gottesman et al. want to conduct this research? 2. Briefly describe the sample used in Gottesman et al .’s research in less than 50 words! 3. Describe the four groups that were analysed in the research. 4. Describe the two sources of secondary data that were used. 5. How did the research team use the information from these two sources? 6. Identify four quantitative results from the study. 7. Outline the conclusions from the study in your own words. 29 Key research: Gottesman et al . (2010) on Genetic explanations