Aetiologies of schizophrenia

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Introduction and physiological explanations

  • Schizophrenia is a mental disorder. Positive symptoms=delusions, hallucinations and mixed emotions. Negative symptoms=poverty of speech and a blunted or flat affect.
  • Physiological explanation is dopamine hypothesis.
  • Seidman (1983): neurones in the brain of schizophrenics are oversensitive to neurotransmitter dopamine.
  • Drug Chlorpromazine useful for treating schizophrenia as blocks dopamine receptors - syggests dopamine causes schizophrenia.
  • Drug L-dopa, used to treat Parkinson's disease increases dopamin levels and leads to symptoms of schizophrenia.
  • Drug Amphamine causes brain to respond as it there was too much dopamine (even though levels are unchanged). Lead to some causes of schizophrenia.
  • However, difficult to assess levels of dopamine in living patients. Done in post mortems - involves inserting needle into spine which is a dangerous technique. 
  • Lindstrom et al (1999): PET scans to assess levels of dopamine in untreated schizophrenics and found had more of neurotransmitter than the control gorup.
  • Gjedde and Wong (1987): schizophrenic have twice as many dopamine receptors compared to controls.
  • However, studies dont show cause and effect. But may be reliable as use brain scanning.
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Psychological explanations

  • Double-bind theory. Bateson (1956): children who receive contradicotry messages from parents likely to develop schizophrenia. E.g. if mother told her child she loved him whilst turning her head in disgust, child will get confused leading to schizophrenic symptoms e.g. withdrawal.
  • Lidt et al (1965): schizophrenia occurs as a result of destructive parental interactions with their children.
  • Berger (1965): schizophrenics reported higher recall of double-bind statements from their mothers than non-schizophrenics. However their shcizophrenia could cause them to see their parents behaviour as negative.
  • Mischler and Waxler (1968): mothers talking to their schizophrenic daughters were aloof and unrepsonsive. Talking to their non-schizophrenic daughters they wer emore repsonsive - Schizophrenics treated differnetly by parents. However, gender biased as only metions daughters.
  • Stressful life events. Birley (1968): if schizophrenics had a subseqeunt attack they reported twice as many stressful life events compared to the control group.
  • Day et al (1987):schizophrenics experienced many life events. Good study to use as completed in many countries (no culture bias) so can be generalised to other schizophrenics.
  • Conclusion - diathesis-stress model. More than one cause. Biological predisposition and stressful life event.
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