Two Biological Explanations of Schizophrenia Essay
487 Words2 Pages
Two Biological Explanations of Schizophrenia
There are many biological explanations of schizophrenia. In this essay I will concentrate on the genetic explanation and biochemical explanation of the disorder. There are many studies that look in to genetics and the link to schizophrenia. This is dues to an original finding that schizophrenia runs in families and therefore suggests that genes are responsible for the disorder. I study was preformed by Janicak et al 2001; they found that monozygotic twins have a 48% concordance rate. This is considerably less in dizygotic twins where the concordance rate falls to 17%. This would suggest there is a strong case for genetics being involved with…show more content…
Gottesman also supports the genetic link, showing schizophrenia is more common in close biological relatives of a schizophrenic. However genetic explanations cannot account for the patients who have no family history of the disorder.
Biochemical factors are used to suggest that schizophrenia is caused by abnormal neurotransmitter activity. The main aspect of this explanation is the Dopamine hypothesis. Schizophrenia has been linked to with high levels of dopamine in the brain. Dopamine is a neurotransmitter associated with attention. Schizophrenics seem to have an increased number of D2 dopamine receptors on receiving neurons. This theory is support by the fact that Phenothiazines bind with D2 receptors and reduce positive symptoms. Another piece of supporting evidence is that Parkinson’s disease drug L-dopa, increase the level of dopamine and causes schizophrenic like symptoms in some people. However excess dopamine can only explain some types of schizophrenia, usually positive rather than negative. Newer antipsychotic also affect levels of other neurotransmitters. This theory can also not explain why some schizophrenics have long periods of remission.
(a) Outline and evaluate two non-biological explanations of schizophrenia
People diagnosed with schizophrenia come from all types of social backgrounds, but most are clustered
?Outline and evaluate psychological explanations of schizophrenia (24 marks) Brown and Birley studied stressful life events in the role of relapse in schizophrenics. They found that 50% of people experience a stressful life event e. g. death, relationship break-up, job loss etc. in the 3 weeks prior to a schizophrenic episode. A control sample reported a low and unchanging level of stressful life events over the same period. However not all evidence supports the role of life events.
For example, Van Os et al reported that patients were not more likely to have a major stressful life event in the 3 months preceding the onset of their illness. In a prospective part of the study, those patients who had experienced a major life event went on to have a lower likelihood of relapse, further-more life events after the onset of schizophrenia may be a consequence rather than a cause of schizophrenia. Bateson et al (1956) suggested that children who frequently receive contradictory messages from their parents are more likely to develop schizophrenia e. g.
a mother hugs her child but then disapprovingly tells him off for being “clingy”. This is known as the double-bind theory. There is evidence to support the double-bind theory. Berger found that schizophrenics reported a higher recall of double-bind statements by their mothers than non-schizophrenics. However this evidence might not be reliable, as patients recall may be affected by their schizophrenic. Other studies are less supportive. Liem measured patterns of parental communications in families of schizophrenic children and found no difference when compared with normal children.
Expressed emotion (EE) involves high levels of negative emotion (e. g. criticism) or high levels of positive emotion (e. g. over-protectiveness). Linszen at al (1997) found a patient returning to a family with high EE is four times more likely to relapse than a patient returning to a family with low EE. There is an issue as the whether EE is a cause or an effect of schizophrenia. Hogarty et al found that such therapy can significantly reduce intervention was the key element of the therapy or whether other aspects of family intervention may have helped.
Cognitive psychologists think that disturbed thinking processes are the cause of schizophrenia. It is thought that the mechanisms that operate in normal brains filter and process information are defective in the brains of people with schizophrenia. People with schizophrenia have no filter so they let in irrelevant information, which they are unable to interpret correctly. Studies have shown that people with schizophrenia are poor at laboratory tasks which require paying attention to only some stimuli.
However this theory doesn’t really explain the causes of schizophrenia more than just the symptoms of the disorder. Hemsley (1993) suggested that the central deflect in schizophrenia is the breakdown in the relationship between already stored memories and new incoming information. People with schizophrenic cannot activate their schemas so are subjective to sensory overload and do not know which aspects of a situation to attend and which to ignore. There has been promising research with animals offering support for Helmsley’s ideas.
Frith (1992) suggested that people with schizophrenia are unable to distinguish between actions that are caused by external forces and those happening internally. He believes that people with schizophrenic have the inability to generate willed action, the inability to monitor willed action and the inability to monitor the intentions of others. Frith suggests that these processes are part of ‘meta representation’ that allows us be aware of our goals and understand the belief of others. Friths theory has provided a comprehensive framework for explaining the symptoms of schizophrenia. However, the theory is still regarded as speculative.