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Describe and Evaluate Gottesman and Shields
Gottesman and Shields study took place in 1966. They researched schizophrenia in twins
using 16 years' consecutive admissions to a psychiatric hospital.
Their aim was to see whether there was a genetic or environmental influence on the
development of schizophrenia. The research method used was a correlation study and they
studied twins where at least one had schizophrenia, this information was gathered using
psychiatric hospital records. Monozygotic (MZ) twins are identical and dizygotic (DZ) twins
are nonidentical. Gottesman and Shields used blood group, finger prints and how a like
they looked to determine whether each set of twins was identical or not. They tested for
schizophrenia by looking at hospital records, conducting interviews, administering test for
disorganised thinking and using personality tests.
Gottesman and Shields found that MZ twins where one had schizophrenia were much more
likely to both have schizophrenia than DZ twins. This is due to the fact MZ twins share
100% of their genes and DZ twins only share 50%. The concordance rate for MZ twins
was 79% and for DZ twins the concordance rate was nearer 45%. They concluded that
genes play an important role in the development of schizophrenia. As MZ twins share more
genes, if the concordance rate is higher it seems likely to be due to genes.
A strength of this study is that it replicates other studies and the results are supported by
those studies, which means they are likely to be reliable. For example, Kallam found that the
concordance rate of MZ twins was higher than that of DZ twins.
Another strength of Gottesman and Shields work is that they address criticisms of previous
studies by detailing the sampling carefully, so it is understood which twins were chosen and
why. There is a lot of detail given about the different diagnoses, for example they include
whether it was schizophrenia or some other form of psychosis abnormality.
However, Gottesman and Shields' study can be criticised as they chose which data to keep
and omitted other data for various reasons that they outline, which means they were carful to
only include relevant data, but it also means that some data was excluded which could have
biased the results.
Finally, Gotesman and Shields' concluded that genes play an important role in the
development of schizophrenia, however, the concordance rate for MZ twins was only 79%,
not 100%. Therefore, environmental factors also need to be taken into consideration. It can
be argued that because twins share similar backgrounds, environmental factors could be a
huge contributing factor in the development of schizophrenia.
Although Gottesman and Shields study doesn't give undisputable evidence to the notion that
schizophrenia is caused by our genes, it does show that they at least have some form of