Schizophrenia

• Schizophrenia

  • Experienced by 1% of the population

  More diagnosed:

  • Men than women
  • Cities than country side
  • Working class than middle class
• Classification of schizophrenia

  • Cluster of symptoms that are unrelated

  Systems for the classification of mental disorder:

  • WHO, International classification of disease edition 10 (ICD-10)
  • American psychiatric association's, diagnostic and statistical manual edition 5 (DSM-5)
• Classification of schizophrenia

  DSM-5:

  • Positive symptoms - Delusions, hallucinations or speech disorganisation

  ICD-10 - Recognises subtypes of schizophrenia:

  • Paranoid S with powerful delusions + hallucinations
  • Hebephrenic S - Primarily with negative symptoms
  • Catatonic S - Disturbance to movement
• Positive symptoms - Additional experiences beyond ordinary existence

  • Hallucinations
  • Delusions
• Positive symptoms - Hallucinations

  • Unusual sensory experiences
  • Some related to environment or no relation to what senses are picking up from environment
  • E.g. Voices heard normally criticizing them
  • Can be experienced relating to any sense
• Positive symptoms - Delusions

  • Irrational beliefs
  • Common delusions - Being an important historical, religious figure etc.
  • Being persecuted by government or aliens
  • Part or whole of them are under external control
  • Behave in a way that makes sense to them but bizarre to others
• Negative symptoms - Loss of usual abilities and experiences

  • Avolition
  • Speech poverty
• Negative symptoms - Avolition

  • aka. apathy
  • Difficult to begin or keep up with a goal-directed activity - Actions performed in order to achieve a result
  • Reduced motivation

  Andreason - 3 Identifying signs:

  • Poor hygiene and grooming
  • Lack of persistence in work or education
  • Lack of energy
• Negative symptoms - Speech poverty

  • Changes in patterns of speech
  • Recognised by ICD-10
  • Accompanied by a delay in the person's verbal responses during conversation

  DSM - Speech disorganisation:

  • Speech becomes incoherent or speaker changes topic mid sentence
  • Seen as a positive symptom
• Evaluation of schizophrenia - Inter-rater reliability

  Cheniaux et al:

  • Two psychiatrists independent diagnose 100 ppl using DSM and ICD

  Findings:

  • Poor inter-rater reliability
  • Psychiatrist one - DSM - 26 + ICD - 44
  • Psychiatrist two - DSM - 13 + ICD - 24

  Limitation: Poor reliability
• Evaluation of schizophrenia - Validity

  • Criterion validity - If different assessment systems arrive at the same diagnosis for the same person
  • Cheniaux et al - More likely to be diagnosed using ICD than DSM
  • Suggests: S is either over-diagnosed in ICD or under-diagnosed in DSM

  Limitation: Poor validity
• Evaluation of schizophrenia - Co-morbidity

  • S is commonly diagnosed with other conditions

  Buckley:

  • Concluded that around 1/2 people with diagnosis of S also have depression
  • PSTD - in under 30% of cases

  Maybe hard to find difference between S and Depression - For diagnosis

  Classification - D and S can be seen as a single condition

  Limitation: Weakness of diagnosis and classification