Schizophrenia - Clinical Characteristics

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What is Schizophrenia?

Thought process disorder characterised by disruption to perceptions, emotions and beliefs

There is still no single agreed definition. It's thought that it isn't a single disorder, but that it has lots of subtypes.

Acute = sudden onset, behaviour changes rapidly over a few days

Chronic = gradual deterioration in mental health over a long period of time

Clinical Characteristics

Positive symptoms = abnormal behaviours are 'added on'

  • Auditory hallucinations (hearing voices)
  • Delusions (believing things that aren't true) 
  • Thought control (believing that thoughts are being controlled or broadcasted)
  • Visual hallucinations (seeing things that aren't there)
  • Incoherent/disorganised speech
  • Distorted thinking

Negative symptoms = normal behaviours are 'taken away'

  • Social withdrawal
  • Depressive symptoms (lack of energy or interest)
  • Impaired emotions

Issues with Classification and Diagnosis

Main classification systems in use are the DSM-IV and ICD-10. There are differences between the two systems which reduces inter-rater reliability since different clinicians may use different systems.

  • DSM requires symptoms to be present for 6 months. ICD requires symptoms  for 1 month.
  • DSM mentions 5 subtypes, ICD mentions 7.
  • DSM is considered more reliable because it asks for more specific symptoms

The inconsistencies mean that a patient may not recieve the best method of treatment, or may be wrongly diagnosed.


 (consistency of diagnosis)

Interpretation: The DSM states that only one positive symptom needs to be present for diagnosis if it is 'bizzare'.. this leads to problems with reliability

  • Research has found inter-rater reliability correlations of just 0.40 for differentiating between 'bizzare' and 'non-bizzare'. 

Inter-rater reliability: Beck et al (1962) found that agreement on diagnosis of 153 patients between 2 psychiatrists was just 54%. Could be due to vague diagnosis criteria.

Culteral bias: Different classification systems are used in different countries lowering the reliablity. Also, ethnic minorities are more likely to be diagnosed as schizophrenic.

  • Copeland et al (1971) gave the same description of…


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