Describe and evaluate two or more biological explanations of schizophrenia

Describe and evaluate two or more biological explanations of schizophrenia (30 marks)

Schizophrenia is a server disorder that is characterized by disturbances in thought, emotion and behaviour. This idea of schizophrenia came from Krapelin and Bleuer in the later 19 th century. The word schizophrenia comes from the Greek words ‘schizen’ (meaning split) and ‘spren’ (meaning mind). Two major types of schizophrenia are catatonic schizophrenia, where patients alternate between immobility and excitement, and paranoid schizophrenia, where patients possesses delusion such as delusions of grandeur (perhaps seeing themselves as Napoleon) or delusional jealousy, where they might believe their partner is having an affair. (doesn’t explain the ?)

One of the problems in classifying schizophrenia is that the range of symptoms is so wide that different patients sometimes have no symptoms in common. A classic study by Rosenham (on being sane in insane places) also showed that psychiatrists were all too willing to diagnose the disorder despite very limited information on patient’s symptoms. It has even been suggested that American psychologists were 10 times more likely to diagnose schizophrenia than their British counterparts. This leads to the conclusion that the best way to cure oneself of schizophrenia is to cross the Atlantic! (doesn’t answer ?)

A major explanation of schizophrenia is that it is caused by excessive activity of the neurotransmitter dopamine. In schizophrenics neurons that use dopamine fire too often and transmit too many messages. As a result, the symptoms associated with schizophrenia appear. Evidence for the dopamine hypothesis comes from the use of antipsychotic drugs (the dopamine antagonists), which block receptor sites for dopamine and reduce its activity. This reduces the symptoms. Other drugs, such as amphetamines, increase dopamine activity and may lead to schizophrenic-like symptoms. Autopsies of the brains of dead schizophrenics have shown that they have far more dopamine antagonists, ...

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It is believed that brain damage is associated with the negative symptoms of schizophrenia ( eg loss of affect and apathy) rather than positive symptoms (eg hallucinations and speech disturbances). On the basis of this, Crow (1980) suggested that there are two distinct froms of the disorder type 1 (positive symptoms and no brain damage) and type 2 (negative symptoms and evidence of brain damage). This is supported by the fact that drug therapies tend to be more successful with type 1 than type 2 schizophrenics. Evidence from post mortems, CAT and MRI studies has also shown that the most consistent findings relating to brain damage have been concerned with enlarged ventricles (suggesting tissue atrophy). These large ventricles are associated with poor performance on neuropsychological tests and a poor response to drug treatments.

Another explanation for the role of biological factors is the suggesting that neurological abnormalities are caused by infection with influenza virus. Infection by the influenza virus may occur during the fetal development (specifically during the second trimester of pregnancy), where it invades and damages the brain. This explanation is supported by a study In Finland, Mederick et al (1988) compared the rates of schizophrenia in adults for those who had been exposed to influenza during pregnancy during the second trimester of pregnancy, in other trimesters or not at all. Mednick showed that the rate of schizophrenia was much higher in those exposed to the influenza virus during the second trimester. This is the stage at which there is a critical rate of cortical growth in the fetus so damage during this time is likely to have a greater effect than during other periods of pregnancy.

A final explanation of schizophrenia is in terms of genetics. Twin studies have suggested that genetics are very important in determining schizophrenia, although the early twin studies did not take into account of upbringing as a contributory factor in the development of the disorder. Recent explanations from evolutionary psychology have even shown that schizophrenia might have an adaptive function, accounting for its continued existence in the gene pool

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Linda Penn

1st of Apr 2013

The writer has made some good points about the condition of schizophrenia. However to improve the essay it would be advisable for the writer to make a plan. There should be a good definition of schizophrenia at the beginning of the essay, as well as an explanation of the symptoms and behaviour associated with the condition. After the initial introduction, it would then be advisable to give a good explanation about what the biological explanation for schizophrenia includes. Then the writer could discuss further the biological explanations chosen eg. genetics, biochemical factors, brain structures etc. Various referenced studies, some already mentioned, could then be used to back up any statements made. Finally, a conclusion can be drawn using the aforementioned information.

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