Kety et al (1968) Flashcards
What type of study is this?
ADOPTION!!
What is the aim?
To find out if there’s a genetic basis for schizophrenia
How many participants were there?
34
Where were participants recruited from?
Danish adoption register
How old were the participants?
20-43
What were the categories the schizophrenics were split up into?
Chronic schizophrenia (16) Acute schizophrenia (7) Borderline schizophrenia (11)
How many control ppts were there?
33
What were the schizophrenics and controls matched on?
Age, Gender, Age adopted, Class
Who did researchers track down?
Biological and adopted relatives of participants
What type of test was used to diagnose family?
Blind test
What were the conditions the relatives were assigned to after diagnosis?
Adoptive (IA, CA) or Biological groups (IB, CB)
What’s an example of one of the diagnosis categories?
‘uncertain chronic schizophrenia’
What were the results?
- More signs of schizophrenic spectrum disorders in index ppts biological family, rather than adopted family
- More spectrum disorder in index biological family than controls biological family
What can we conclude from Kety’s study?
There’s a genetic basis for schizophrenia because schizophrenia adoptees more likely to have schizophrenia in biological family than adopted family
How is generalisability increased?
Sample of men and women from a range of ages which is representative of target population
How is generalisability decreased?
Hard to generalise to other ethnic groups as sample was homogenous and white
How is reliability increased?
Inter-rater reliability as 4 psychiatrists were used to diagnose relatives (only 4 cases they couldn’t agree but removed)
How is reliability decreased?
Schizophrenia categories were vague and dependent on subjective interpretation
What are the applications of this study?
- If families are away the child has a genetic predisposition, they can steer the child away from environmental triggers e.g., drugs and look out for symptoms
How is validity increased?
Construct validity from diathesis stress model
How is validity descreased?
Joseph (2014) suggests that Kety changed design to get the results he was looking for so findings didn’t measure what they claimed to measure
How does the study violate ethical guidelines?
- No informed consent as participants weren’t directly approached as data analysed under Danish laws
- Issues of social responsibility as they had a responsibility to find out whether there was a genetic component to help society
- Issues of protection from harm/ socially sensitive as Kety suggested that schizophrenia is genetically inheritable which may lead families with mental illness history to experience prejudice
