diagnosis and classification of sz

• positive symptoms of sz

  • atypical symptoms experienced in addition to normal experiences.
  • includes hallucinations and delusions
• hallucinations

  • a positive symptom of sz
  • sensory experiences that have either no basis in reality or are distorted perceptions of things that are there
• delusions

  • positive symptom of sz
  • they involved beliefs that have no basis in reality
  • e.g a person believes that they are someone else or that they are a victim of conspiracy
• negative symptoms of sz

  • atypical experiences that represent the loss of a usual experience such as a loss of clear thinking or a loss of motivation
• speech poverty

  • negative symptom
  • reduced frequency and quality of speech
• avolition

  • negative symptom
  • involves loss of motivation to carry out tasks and results in lowered activity levels
• comorbidity

  • occurrence of two disorders or conditions together
  • e.g a person has both schizophrenia and a personality disorder.
  • where two conditions frequently diagnosed together it calls into question the validity of classifying the two disorders separately
• symptom overlap

  • occurs when two or more conditions share symptoms.
  • where conditions share many symptoms, this calls into question the validity of classifying the two disorders separately
• reliability

  Measures consistency. It is about the extent to which psychiatrists can agree on the same diagnoses when independently assessing patients.
• validity

   Is all about measuring what you want to measure, in our case how accurate diagnosis for schizophrenia is. If you create a test that does not measure schizophrenia then it is not valid
• Issues with reliability first arise as both these tools have different diagnostic criteria’s; for example the DSM tool previously recognised 5 sub-types of schizophrenia while the ICD tool recognised 7 subtypes. Although now updated, this means diagnosis was not consistent between different parts of the world dependent on the tool being used. This means one country may have diagnosed someone as normal while another place with the same symptoms may see them as Schizophrenic. Therefore there is a clear cultural bias dependent on which identification tool is being used