Clinical Characteristics, Issues of Reliability and Validity, Biological Explanations, Biological Therapies, Psychological Explanations, Psychological Therapies

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  • Created on: 09-06-11 09:35
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Clinical Characteristics of Schizophrenia (5 marks only)
Diagnostic and Statistical Manual of Mental Disorders (DSM) criteria for the diagnosis of
1) Two or more symptoms for a significant amount of time during a one month period.
2) Symptoms include positive symptoms such as delusions and hallucinations and
negative symptoms such as affective flattening and alogia.
3) If delusions are bizarre or hallucinations involve two or more voices conversing with
each other, then only one symptom is required.
4) Symptoms must have a negative impact on one or more major areas of functioning,
such as work or interpersonal relations.
5) Other causes must be excluded, for example, drugs or a brain tumour.
Issues of Reliability and Validity for Classification and Diagnosis
Reliability and the DSM AO1
Reliability refers to the extent to which the classification and diagnosis of
schizophrenia is consistent amongst different people.
The DSM is designed to create a more reliable system of diagnosis for mental
illness including schizophrenia.
This is because psychologists all use the same diagnostic criteria so that a
diagnosis of schizophrenia should be consistent with all psychologists who use the
However research has found that this is not necessarily the case...
Klosterkotter et al (1994): Positive or Negative AO2
Procedure: Assessed 489 admissions to a psychiatric ward.
Findings: Negative symptoms were a more unreliable basis for a diagnosis of
schizophrenia than positive symptoms.
Conclusion: It is possible to give individuals with totally different behaviours (i.e.
different combinations of the characteristic symptoms) the same diagnosis of
Bizzare AO2
The DSM diagnostic criteria of `bizarre' symptoms can be difficult to interpret,
making the diagnosis less reliable.

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Procedure: 50 senior psychiatrists were asked to differentiate between `bizarre' and
Findings: Interrater reliability correlations of only 0.40.
Conclusion: Suggests this diagnostic requirement is not a reliable method of
distinguishing between schizophrenic and nonschizophrenic patients.
Copeland et al (1971): Cultural Variations AO3
Procedure: 134 US psychologists and 194 British psychologists given a description
of a patient.
Findings: 69% of the US psychologists diagnosed schizophrenia compared to only
2% of the British psychologists.
Conclusion: Diagnosis varies between countries and could therefore be considered
unreliable.…read more

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Conclusion: Suggests that diagnoses of schizophrenia have low validity as
`schizophrenic' symptoms are also present in other disorders.
Predictive Validity AO2
Diagnosis of schizophrenia has low predictive validity.
Predictive validity refers to the extent to which people diagnosed with schizophrenia
have the same prognoses (outcomes).
Research suggests that:
20% of people diagnosed with schizophrenia recover their previous level of
10% achieve significant and lasting improvement.
30% show some improvement with intermittent relapses.
This supports the criticism that a diagnosis of schizophrenia has low validity.…read more

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Reduced function of the NMDA glutamate receptor linked to the onset of
Linked to dopamine as dopamine receptors inhibit the release of glutamate (see saw
Javitt et al (2000): See Saw Effect AO2
Procedure: Administered rats with glycine which increases the amount of glutamate
in the brain.
Findings: Increased dopamine in brain and reduced pychosis.
Conclusion: Supports theory that decreased glutamate levels and increased
dopamine levels lead to the onset of schizophrenia.…read more

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Conclusion: Suggests that genetic factors play a much greater role than
environmental factors.
Reductionist AO3
Reduces schizophrenia to an imbalance of chemicals the brain and ignores other
For example, Frith proposes a cognitive explanation of schizophrenia which involves
problems with metarepresentation ­ the ability to distinguish between external
speech and internal thoughts.
This suggests that the biological theories of schizophrenia cannot provide a complete
explanation.…read more

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Procedure: Meta analysis of over 100 studies that compared antipsychotics with
Findings: More than 70% of sufferers treated with antipsychotics improved in
condition after 6 weeks while less than 25% improved with placebos.
Conclusion: Suggests that antipsychotics have a beneficial medical effect despite side
Self Medication AO3
The main problem with drug therapy as a treatment for schizophrenia is...
Only effective if patients are consistent in taking the drugs.
Many patients may not take the drugs regularly, often because of side effects.…read more

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Findings: ECT has between 6080% effectiveness against specific categories of
schizophrenia and between 20 and 30 sessions is needed in order to be this
effective, as opposed to 15 for other disorders.
Conclusion: ECT is only appropriate for some patients with specific types of
Side Effects AO2 include in previous paragraph
Bilateral ECT, which is more effective than unilateral ECT, can have side effects
such as short term memory loss with 1% of patients suffering severe memory loss.…read more

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This distancing from reality may lead to such people being labelled as schizophrenic
and then behaving so as to meet the requirements of the label (Scheff's labelling
Ulman and Krasner AO2
Findings: Staff in hospital paid more attention to patients who displayed
characteristics of the disorder.
Conclusion: Suggests that schizophrenia is learnt through reinforcement of abnormal
behaviour.…read more

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Procedure: Tested the theory that positive symptoms of schizophrenia are caused by
problems of metarepresentation.
Findings: Schizophrenics struggled to identify words as ones which they had created
themselves or ones they had not seen before.
Conclusion: Supports Frith's theory that schizophrenics have difficulty distinguishing
external information (words they had read) and internal information (words they had
created) ­ in other words, problems of metarepresentation.…read more

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These show links between the sufferer's thoughts, actions and emotions and are
used to reduce the anxiety of patients about their `bizarre' symptoms.
Trower et al (2004): AO2
Procedure: Controlled trial of CBT
Findings: The therapy did not reduce the intensity of hallucinations but did make
them seem less threatening. Also found that CBT reduced both positive and negative
symptoms of the disorder and improved patients' quality of life.…read more


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