PSY4 aetiologies of schizophrenia essay

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Nikita Chudasama
Discuss the aetiologies of Schizophrenia including physiological and psychological explanations
Schizophrenia is a severe mental disorder that interrupts people's natural flow of life and makes it
nearly impossible for them to function normally. Those suffering from schizophrenia are incapable of
separating reality from what they are imagining. They often hear voices, suffer from hallucinations,
and have strange or even paranoid delusions, and their thinking and speech have no rhyme or reason.
As there has been an everlasting debate between whether schizophrenia is biological, or
due to environmental impacts, there are many case studies which highlight a connection between
schizophrenia in parents and their offspring later developing schizophrenia. A way to separate out
the effects of environmental and genetic factors is to look at adopted children who develop
schizophrenia and compare them with their biological and adoptive parents. The Finnish adoption
study, which Tienari began in 1969 identified adopted offspring of biological mothers who had been
diagnosed with schizophrenia, (hundred and twenty-two of these studies), these where then
compared with the control group (hundred and thirty five) adopted offspring whose mothers did not
have any mental disorder. The study then later on reported that seven percent of the hundred and
twelve cases developed schizophrenia. This study suggests that you are more likely to inherit
schizophrenia if your biological parents suffer from schizophrenia. Moreover, A Danish Adoption
Study, conducted by Kety et al (1994), taking a national sample from across Denmark, found high
rates of diagnosis for chronic schizophrenia in adoptees whose biological parents had the same
diagnosis, even though they had been adopted by `healthy' parents. The data provided by these
studies have indicated a strong genetic link for schizophrenia. This further supports the physiological
explanation of schizophrenia.
Furthermore, Heston (1947) studied forty seven children born to schizophrenic mothers but
who were then separated from them within the first three days of life. They were adopted into
families not related to the biological mothers. Later in life they were compared with a control group
of children who had been separated in similar circumstances at birth, but crucially, not born to
schizophrenic mothers. Five of the forty-seven in the experimental group had gone on to develop
schizophrenia (over 10%), whereas none of those in the control group had developed the disorder.
This goes to show that there is a strong genetic link in developing schizophrenia, as a person is more
likely to develop schizophrenia, if their biological parents, whose genes they posses has
schizophrenia, rather than the parents who had adopted them and brought them up; environmental
factors do not have a significant impact and genetics plays a definite role in development of
schizophrenia. A few weaknesses include: bias because of knowledge of previous family diagnosis of
schizophrenia; issues with demand characteristics and reliability issues. It is also hard to separate
influences of nature vs. nurture, as concordance rates are not 100% so it cannot be explained fully by
genes. It is also lack population validity as the studies were conducted on a small sample from
selected families.
Using PET, MRI and CAT scans researchers have discovered that many schizophrenic patients have
enlarged ventricles; these are cavities in the brain that supply nutrients and remove waste. Also, the
ventricles of a person with schizophrenia are on average 15% bigger than normal. Brown et al (1986)
found decreased brain weight and enlarged ventricles, these cavities hold cerebrospinal fluid. A
strength of the large ventricles is that the research into the ventricles and neurotransmitters have
high reliability, this is because research is carried out in highly controlled environments with
specialists and high tech equipment, they take accurate readings or brain regions such as frontal and

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Nikita Chudasama
prefrontal cortex, this suggests that research was tested and restarted and the same results would
occur. Moreover, supporting evidence for brain structure comes from empirical support from
Suddath et al (1990), he used MRI scans to obtain pictures of brain structure of twins where one was
schizophrenic, and one twin had generally large ventricles and reduced hypothalamus.…read more


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