the genetic explanation for schizophrenia -biological explanation Flashcards
what does the genetic explanation for schizophrenia say
people with a close relative that has schizophrenia are more likely to have schizophrenia than someone with no family history of the disorder
what does a polygenic disorder mean
there is no single gene that is responsible for a disorder
who carried out a meta analysis
Ripke et al
whats a meta analysis
combining results from previous studies
what dis Ripke et al do
carried out a meta analysis of genome-wide studies of schizophrenia the genetic makeup of 37,000 with schizophrenia was compared to 113,000 controls
what did Ripke et al find
that there are 108 separate genetic variations linked with increased risk of schizophrenia. These candidate genes associated with increased risk included those coding for the functioning of a number of neurotransmitters including dopamine
what are the evaluation points to support the genetic explanations of schizophrenia
Gottesman
Tienari et al
occur in people with no family history of the disorder
nature vs nurture
explain the what Gottesman did to support the genetic explanation
he carried out a large scale family study, he pooled the data from 40 European studies published between 1920 and 1987. He conducted a meta analysis of genetic influences on schizophrenia
How does Gottesman’s research support the genetic hypothesis
the closer you are to the person with schizophrenia the more likely you are to have schizophrenia. people you share the most genes with, your chance of schizophrenia increases
what is an issue with Gottesman’s meta analysis
the DSM is constantly changing so they change how they diagnose. They refine and adapt it all the time. Therefore you don’t know if they still diagnosed schizophrenia the same way throughout the 67 year period
can we say nurture plays a part looking at Gottesman’s data
yes because for identical twins the risk of developing schizophrenia is not 100% it is 48%
why would it be wrong to assume that the cause of the disorder is only genetic and not environmental
family’s don’t only share genes but are similar in other ways as well.
they live in the same environment so if its an environmental stressor causing schizophrenia they would all be around the stressor
explain the study by Tienari et al
They investigated the combination of genetic vulnerability and parenting style as a potential trigger in children with a high risk adopted from 19,000 Finnish mothers with schizophrenia. the sample consisted of 303 families where adoptive parents were assessed for their child rearing style, levels of criticism, conflict and empathy
Rates of schizophrenia in high genetic risk adoptees were compared to a control group of adoptees with low genetic risk of developing schizophrenia
in the Tienari et al study what were the parents assessed on
child-rearing style
measuring levels of criticism, conflict and empathy
what were the finding of Tienari et al
high genetic risk adoptees showed higher rates of developing schizophrenia compared to the control group, regardless of the family functioning score
High genetic risk adoptees showed higher rates of developing schizophrenia in a family with a high conflict score compared to a family with a low conflict score
why does Tienari et al’s research strengthen the evidence for the role of genes
even when the effects of nature and nurture are separate, those with a genetic vulnerability due to a parent with schizophrenia are more likely to develop the disorder also suggesting family conflict may make those with schizophrenia more likely to develop in those with the genetic vulnerability
in Tienari et al’s study what was the most vulnerable group
high conflict in families and genetic vulnerability to schizophrenia
explain the evaluation point that schizophrenia can occur in people without a family history of the disorder
a mutation in a parents DNA, for example this could be in the fathers sperm cells. This could be due to radiation, poison or viral infection. The mutated DNA is then passed onto the child leading them to develop schizophrenia later on
who supported the evaluation point that schizophrenia can occur in people without a family history of the disorder and what did they find
Brown et al found a positive correlation between paternal age and risk of schizophrenia, increasing from 0.7% with fathers under the age of 25 to over 2% in fathers over 50
explain the nature nurture debate for how schizophrenia may be caused by an interaction between genes and the environment
this links to the diathesis-stress model. if someone has a gene that makes them vulnerable to schizophrenia and has an environmental stressor present, this could be childhood sexual and physical abuse, family conflict, significant life changes. when the diathesis and stressor interact it leads to the development of schizophrenia
explain the research into maternal exposure to the flu virus while pregnant
exposure to the flu virus during pregnancy increases the risk of schizophrenia in the child this is thought to cause inflammation during the critical period of brain development
