Kety et al powerpoint schizophrenia

Kety et al
Copenhagen High Risk Study
Kety conducted a longitudinal study in Denmark 1962.
Kety and colleagues identified 207 offspring mothers
diagnosed with schizophrenia high risk group), along with
this matched a control of 104 children with “healthy
mothers” All children were aged between 10-18 years at
the start of the study (in 1962– hence a matched pairs
Children (schizophrenic mother children vs healthy
mother children) were matched on age, genders, parental
socio-economic status, ruban/rural residence
Due to the longitudinal nature of the study- children were
followed up in 1974, and further in 1989
• Schizophrenic was diagnosed 16.2% in the high risk group,
compared to 1.9% in the low risk group
• Identified a Schizotypal personality disorder- which is a
disorder characterised by ecentric behaviour and anomalies
of thinking resembling symptoms of schizophrenia. Kety
infact diagnosed a schizotypal personality disorder in 18.8%
of the high risk group, compared to only 5% of the low risk
• Combining figures for the two disorders i.e. Schizophrenia
itself and the Schizotypal personality disorder- found that
the high risk group had 35% of participants with either/or,
in comparison to the low risk group with only 6.9% of
• The high risk group (children with
schizophrenic mothers) are more likely to
develop schizophrenia compared to the low
risk group (control group of healthy mothers).
Therefore, this shows that genetics play a role
in the development of schizophrenia.
However Kety only concluded with a
correlation, not infact a causal relationship.
A strength of Ketys study is that she matched the children (schizophrenic
mother children vs control group) on relevant variables including parental
socio-economic status, and urban/rural residence. Matched upon these
variables because low socio-economic status and urban environments are
known to be risk factors in developing schizophrenia. Therefore, by controlling
these factors, it shows that the relationship observed of children having
schizophrenia/schizotypal disorder was primarily due to the genetic
component (of mothers having schizophrenia)
Nature vs Nurture debate- despite Kety’s study being a large well controlled
study, and longitudinal, we still encounter problems. The main difficulty with
family studies is that we cannot differentiate the genetic and environmental
influences, because children share the same environment as their mother
Reliability of diagnosis- the diagnosis of schizophrenia is not always reliable.
The mothers of schizophrenia had all been diagnosed with schizophrenia
before modern diagnostic systems were available, so it is possible that they
varied widely in their symptoms. It might even be the case that they would not
have been given this diagnosis at all if later criteria had been used.

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