Kety Flashcards
What is the aim of Kety?
To see if there is a genetic-basis for schizophrenia
To see if there is a higher rate of schizophrenia-related illnesses among biological relatives than adoptive relatives
What is the sample of Kety?
34 schizophrenics (2 MZ twins) from Danish Adoption Register, Copenhagen, aged 20 to 43
B1: 16 with chronic schizophrenia
B2: 7 with acute schizophrenia
B3: 11 with borderline schizophrenia
33 mentally healthy controls matched on age, gender, age adopted and social class of adoptive family
What is the procedure of Kety?
Tracked 463 relatives and assessed their mental status (using mental health register)
4 psychiatrists used medical records to diagnose family members - blind test
Participants assigned to either adoptive family groups (IA and CA) or biological family groups (IB and CB)
4 psychiatrists diagnosed family based on medical records and classified as schizophrenic or not - couldn’t reach a conclusion of 4 so they were dropped
What are the results of Kety?
Grouped relatives in B1-B3, D1-D3 and C categories as “schizophrenia spectrum disorders”
More signs of schizophrenic spectrum disorders in index participants’ biological than adoptive family
13/150 biological relatives of index cases had diagnosis of schizophrenia, uncertain schizophrenia, or inadequate personality
3/156 biological relatives of controls had diagnosis of schizophrenia, uncertain schizophrenia, or inadequate personality
What are the conclusions of Kety?
There seems to be a genetic component to schizophrenia
Schizophrenia adoptees more likely to have schizophrenia in biological than adoptive family
Index cases’ biological families more likely to have schizophrenia than families of control
Why is it good that Kety used 4 psychiatrists?
High in inter-rater reliability as they agreed where to assign relatives in B1-B3, D1-D3, C
Why is it a weakness that Kety used “schizophrenia spectrum”?
Umbrella term, doesn’t measure schizophrenia directly so reduces validity of findings as we might not be measuring schizophrenia
How is Kety’s study high in test-retest reliability?
Replicated study in 1975, 1978 and 1994 (adding interviews) and got similar findings so results about influence of genetics on schizophrenia are more reliable
Why is Kety socially sensitive?
Creates impression that schizophrenia is genetically heritable so leads to stress, anxiety and prejudice for people from families with history of mental illness
What is good about Kety’s sample?
Fairly large sample using adoptees with schizophrenia whilst covering a range of ages and both genders so results about genetics on schizophrenia are more generalisable
What is a weakness about Kety’s sample?
Ethnocentric (all from Danish Adoption Registry and Denmark) so results about how genetics influence schizophrenia are not applicable to wider population from other places
