Schizophrenia Chapter Summary

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Classification and Diagnosis

Nature of Schizophrenia:

  • Profound disruption of cognition and emotion
  • Affects language, perception, affect and sense of self
  • Association with violence = media invention
  • 8% of schizophrenics commit a serious act of violence
  • Less than other mental disorders 
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Classification and Diagnosis

Diagnostic Criteria:

  • Positive symptoms = excess or distortion of normal symptoms - delusions, experience of control, hallucinations and disordered thinking
  • Negative syptoms = loss of normal functions - affective flattening, alogia and avolition
  • Diagnosis:
    •  
      • Two or more positive symptoms 
      • Social/occupational dysfunction
      • At least six months
      • Exclusion of mood disorders
      • Exclusion of organic cause 
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Classification and Diagnosis

Reliability:

  • Extent to which psychiatrists can agree on the same diagnosis
     
  • DSM claims increased reliability of diagnosis
     
  • Whaley (2001) - inter-rater reliability as low as 0.11
     
  • Klosterkotter et al (1994) - positive symptoms are more useful for diagnosis
     
  • Mojabi and Nicholson (1995) - low inter-rater reliability of 'bizzare' vs 'non-bizzare' symptoms
     
  • Rosenhan's study highlights the problem - Being sane in insane places
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Classification and Diagnosis

Validity:

  • Concerns over what schizophrenia really is
  • First-rank symptoms distinguish schizophrenia from other disorders
  • Also found in other disorders such as DID
  • Little evidence of shared prognosis in schizophrenia
  • Low predictive validity 

Synoptic Link:

Copeland (1971) - reliability challenged by difference between UK and US diagnoses 

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Biological Explanations

Genetic Factors:

  • Gottesman (1991) - more common among biological relatives
  • Joseph (2000) found concordance rate of 40% for MZ twins and 7% for DZ
  • 'Blind' diagnosis produces much lower concordance rate for MZ but still higher than DZ
  • Tienari et al (2000) if biological mother schizophrenic, 6% of adoptees are also schizophrenic, with 2% of controls

Evaluation:

  • Environments for MZ twins may be more similar than DZ
  • Differences in concordance rates may reflect environmental similarity rather than role of genetic factors 
  • Adopted childen from schizophrenic backgrounds may be adopted by particular type of adoptive parent, making conclusions difficult to draw 
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Biological Explanations

Dopamine Hypothesis:

  • Neurons that transmit dopamine fire too easily/often leading to symptoms
  • Schizophrenics have abormally high levels of D2 receptors
  • Amphetamines cause hallucinations and delusions (dopamine antagonist)
  • Antipsychotic drugs - block dopamine and eliminate symptoms
  • Parkinson's disease - treatment raises dopamine levels and trigger schizophrenic symptoms

Evaluation:

  • Drugs can increase schizophrenia symptoms as neurons try to compensate 
  • Haracz (1982) found elevated dopamine levels in post-mortems of schizophrenics who had taken medication before death
  • Neuroimaging studies failed to provide convincing evidence for altered dopamine activity in schizophrenics 
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Biological Explanations

Enlarged Ventricles:

  • 15% bigger in schizophrenics than non-schizophrenics
  • Display negative rather than positive symptoms
  • Result of poor brain development or tissue damaging

Evaluation:

  • Meta-analysis found substantial overlap in ventricle size among schizophrenics and control populations
  • Enlarged ventricles may be due to effects of antipsychotic medication
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Biological Explanations

Synoptic Links:

  • Many studies have to show 'schizophrenia spectrum disorders' to show genetic influences
  • Evolutionary perspective - schizophrenia may have an adaptive advantage (group splitting hypothesis) 
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Psychological Explanations

Psychological Theories:

  • Psychodynamic view: result of regression to a pre-ego stage and atempts to re-establish ego control
  • Some symptoms reflect infantile state, others are an attempt to re-establish control
  • Further features appear as they try to understand their experiences
  • May reject feedback from others and develop delusional beliefs

Evaluation:

  • Very little evidence to support psychodynamic view
  • Behaviour of parents = key influence in development but may be a consequence rather than a cause
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Psychological Explanations

Socio-Cultural Factors:

  • Patients report twice as many stressful life events prior to schizophrenic episode
  • Double-bind theory - contradictory messages from parents
  • Expressed Emotion - family communication style 
  • Leads to stress beyond impaired coping mechanisms
  • Labelling theory - symptoms of schizophrenia seen as deviant from the rules

Evaluation:

  • Link between life events is only correlational
  • Berger (1965) schizophrenics recall more double-bind statements from mothers
  • Scheff (1974) - 13 out of 18 studies consistent with predictions of labelling theory 
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Psychological Explanations

Synoptic Link:

  • Must less common in non-individualistic cultures (EE)
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Biological Therapies

Anti-psychotic medication:

  • Conventional = reduce effects of dopamine and so reduce symptoms
  • Bind to D2 dopamine receptors but do not stimulate them
  • Atypical = temporarily occupy D2 receptors then dissociate to allow normal transmission
  • Leads to lower levels of side effects

Evaluation:

  • Davis et al (1980) higher relapse rates in patients who had placebo rather than drug
  • More effective for hostile home environments
  • Conventional = 30% develop TD
  • Motivational deficits - prevents positive actions
  • Leucht et al (1999) - superiority of atypical over conventional only moderate
  • Atypical = marginal support for effectiveness with negative symptoms
  • Atypical = lower TD rates
  • Patients more likely to continue with less side effects 
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Biological Therapies

ECT:

  • Karagulla (1950) - first studies were disappointing
  • Recovery lower than control group
  • Tharyan and Adams (2005) - found 'real' ECT more effective than 'sham' ECT
  • Combined with medication for rapid reduction in symptoms

Evaluation:

  • Effectiveness = inconsistent
  • APA study found no difference between effects of ECT and antipsychotic medication
  • Sarita et al (1998) - no difference in symptom reduction between ECT and simulated ECT
  • Risks of ECT
  • Use has declined 
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Biological Therapies

Synoptic Links:

  • Ross and Read (2004) - placebo not a fair test because proportion of relapses explain by withdrawal effects
  • Ethical issues - human rights issues associated with TD 
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Psychological Therapies

CBT:

  • Patients trace back origins of symptoms to understand how they developed
  • Evaluate content of delusions/hallucinations
  • Develop own alternatives to maladaptive beliefs
  • Outcome studies show that patients receving CBT experience fewer hallucinations/delusions than those recieving antipsychotic medication alone 
  • Lower patient drop-out rates and greater satisfaction 

Evaluation:

  • Meta-analysis found significant decreases in positive symptoms after CBT
  • Most studies involved antipsychotic medication - hard to judge CBT alone
  • Older patients less likely to benefit 
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Psychological Therapies

Psychodynamic Therapies:

  • Based on assumption that individuals unaware of influence of unconsious conflicts on their current psychological state
  • Creates an alliance with patients by offering to help with the problem
  • Build trust by replacing harsh parental conscience with more supportive one
  • Patients takes more active role

Evaluation:

  • Gottdiener (2000) - 66% improved after treatment, 35% didn't
  • Some forms can be harmful
  • Contradictory findings
  • Appropriate when combined with medication
  • Long and expensive - may have benefits in that it helps patient to seek employment 
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Psychological Therapies

Synoptic Links:

  • Methodological limitations of outcome studies - lack of random allocation
  • Ethical issues - placebo as denied effective treatment  
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