Biologicalš§ ā¢ Kety et al. Study (1968) Flashcards
What is Schizophrenia?
Schizophrenia is a mental illness that affects up to 1% of the UK population, it involves a separation from reality and a breakdown of the personality.
What was the aim of the study?
Whether schizophrenia was more prevalent in biological or adoptive faimilies, in order to discover if it is catalysed by nature (biology/ genes) or nurture (environments/ learnt)
- To identify if there is an increased rate of schizophrenia related ilnesses amongst biological relatives vs adoptive relatives
What were the schizophrenic adoptees referred to during the study?
Index Participants (IP)
What type of experiment was the study?
A Natural Experiment as both the Schziophrenia * Adoption were both naturally occuring instances for the participants
What was the Independent Variable?
(What you change)
The participants, there were two types:
* Index Participants (Schizophrenic Adoptees)
* Control Participants (Mentally Heathly Individuals)
The type of participant was what was changed
What was the Dependent Variable?
(What you measure)
The study measured the prevelance of schizophrenia among 463 family members via interpretation of medical records
Where was the study held and why?
Denmark, this was chosen as for the study to work they required medical record access alongside access to the Danish Adoption Register.
- Denmark was chosen as it has a very good record of adoptive families that is open for the public to view + it has no ethical laws against looking into medical records, it would have been deemed unethical in the UK
What was the sample for the study?
Opportunity Sample
34 Schizophrenic patients/ (Index Participants) taken from Danish Adoption Register, aged 20-43
Different groups:
* B1 - 16 with chronic (long tem) schizophrenia
* B2 - 7 with acute (shorty term) schizophrenia
* B3 - 11 with borderline schizophrenia
Also include 33 mentally healthy controls selected from the register.
So 67 in Total
What were the controls and the Index Participants matched on?
- age of adoption
- gender
- social class
What is the design for the study?
-
Independent Groups
As it looks at the difference between 2 separate groups: biological relatives vs adoptve relatives of the Index Particpants
Why is the study not a Matched Pairs Design?
Because dispite the controls and Index Participants being matched, their results are not individuallty compared one-to-one as pairs, therefore the Design of the experiement = Independent groups as the results of the GROUPS are compared, not individuals
What was the procedure of the study?
- Kety tracked down 463 relatives and used the** Danish Medical Records** to assess their mental health
- There was a panel of 4 Danish Psychiatrists who used the records to diagnose the family (Blind test as they didnt know if records were biological or adoptive faimilies)
- After diagnosis they were reassigned back into clear groups e.g. Adoptive relative for Index Participants, Biological relative etcā¦
What were the 7 categories for diagnosisā for the family members?
(PROCEDURE)
(B1-3 SAME AS INDEX)
* B1 - chronic (long tem) schizophrenia
* B2 - acute (shorty term) schizophrenia
* B3 - borderline schizophrenia
* D1 - uncertain chronic schizophrenia
* D2 - uncertain acute schizophrenia
* D3 - uncertain borderline schizophrenia
* C - āindequate personalityā
What were the results of the study?
All relatives in B1-3 & D1-3 + C labelled as having Schizophrenic Spectrum Disorders (SSD)
- Found more signs of SSD in Idex Participantsā BIOLOGICAL family than adoptive family
*Also found more SSD in Index Participantsā biological families than in the CONTROLS biological families - this is commonly referred to as a** āfive foldā** prevelance of Schzio, a massive difference (Shown below ā)
What was the conclusion for the study?
- There seems to be a GENETIC/BIOLOGICAL component to schizophrenia as the Index Participants were more likely to have schizophrenia in their BIOLOGICAL FAMILY than their adoptive family
- The āfive foldā prevalence of Schizophrenia in Index Bio relatives compared to Control Bio relatives infers that Schizophrenia is again heavily influenced by Genes and is hereditary, that it is more likely to conract if a bio relative has had it
Thus, Kety concluded that Genetic factors (Nature) are important in the transmission of Schizophrenia
Ultimatley inferring that Schizophrenia is determined by Nature (genes), not nurture (learned behaviours)
What is the Generalisability of the study?
- Sample fairly large (34 Index Participants + 33 Controls so 67 total) and covers a wide range of individual differences such as gender and age so it is quite representative
- Sample taken from Danish Adoption Register, making results representative of Danish populationsā tendancy for schizophrenic inheritance, although this means it is not representative of other regions of the world such as the US, ethnocentrism inhibitis generalisability
- + Danish population very stable and homogenous (due to very low levels of migration): mostly white - harder to generalise results to other ethnic groups/ regions with more diverse populations, therefore =** ethnocentrism, also leading to low generalisabiltiy + population validity **
What is the Reliability of the study?
- Test-Retest Reliability - Kety developed very replicable procedure (therefore reliabile) with the prodcedure being replicated on 3 additional occasions after the original 1968 experiment, other experiments got similar findings therefore Test-Retest Reliabiliy
- Inter-Rater Reliability - Within procedure Kety used 4 psychiatrits to diagnose each relative, lowering subjectivity and increasing objectivity of results
What is the Application of the study?
- Findings of the study suggest Sizchophrenia most certianly has a hereditary genetic component; however additional research implies that despite genetic link its only a predispotition and requires a trigger for it to take force
- EARLY INTERVENTION - Therefore studyās findings can be applied to make families aware of a childās predisposition to schizophrenia so that they may guide them away from potential triggers e.g. drugs & alcohol
What is the Validity of the study?
- Sample Attrition - if relatives or participants were too difficult to diagnose they were simply removed from the sample/ experiment - consequently lowering the representvity and population validity as the sample would consist of individuals with āsimpleā cases of schizophrenia, not more complicated ones therefrore = not representative or generalisable
- Construct Vailidity - results match with what was proposed in theory, that schizophrenia will have a genetic component
- Lack of Internal Validity - researchers didnt take into consideration environmental factors or personal history into detail, they only depended on medical records - meaning they were reductionist and lacked internal validity (Control/ acknowledgement of extraneous varaibles that could impact results)
- Increased Validity - Due to it being a blind test, the 4 psychiatrists did not knowf records were biological or adoptive faimilies whilst diagnosing, removing sujectivity and increasing objectivity of diagnosis, therefore increasing validity of results
What are the Ethics of the study?
- All participants in study were NOT directly approached or asked for their consennt on their data use. BUT their data was analysed and used āconsensuallyā under the Danish Laws, technically making the study ethically sound despite lack of informed consent
- Societal Ethical Harm - If Kety created a false impression that schizophrenia is genertically heritable many people may start to become anxious and prejudice towards families with a history of the illness may arise - had a social responsibility for experiment & study to have intergity to ensure findings were truthful to not forge false-hope
- Determinisitc - the studyās findings may lead people to start labelling others as more prone to having a mental illness - possibly leading to prejudice in work place e.g. refusal to hire etcā¦
