Classification and Diagnosis

• Schizophrenia

  • a mental disorder which affects emotions and thoughts to the point where people lose contact with reality
  • 1% of the population is affected by it at some point in their life.
  • Normally diagnosed between the ages of 15-35 with both genders affected equally.
• DSM-5

  • A clinician would use this as a manual to diagnose schizophrenia.
  • The most commonly used in America.
• ICD (International Classification of Diseases)


  The most commonly used diagnostic manual used in Europe
• Classification 


  The grouping of symptoms into categories which helps facilitate a diagnosis.
• DSM-V (5) criteria for Schizophrenia

  Requires 2 or more of the following symptoms to be apparent for six months:

  • Hallucinations
  • Delusions
  • Disorganised Speech
  • Catatonic Behaviour
• Validity


  accuracy of a measurment.
• How could you test the validity of a schizophrenia diagnosis?

  Criterion validity – How accurately a test measures the outcome that it is designed to measure.
• Research suggests…


  Schizophrenia is either over- or underdiagnosed according to the diagnostic system that has been used.
• Research for validity of schizophrenia diagnosis

  Osorio et al (2019) found that there was excellent agreement among clinicians when they used two measures to diagnose schizophrenia which both came from DSM system.

  This suggests that Criterion validity for diagnosing schizophrenia is good provided it takes place within a single diagnostic system.
• Comorbidity 


  The occurrence of two disorders of conditions together, for example, if someone has both schizophrenia and depression.
• Why is comorbidity an issue with the diagnosis of schizophrenia?

  If conditions occur together a lot of the time then it questions the validity of their diagnosis and classification as they may actually be a single condition.
• Research comorbidity - Buckley et al 


  Found that half of those diagnosed with schizophrenia had a diagnosis of depression or substance abuse.
• Culture Bias 


  The interpretation of situations, actions or data based on the standards of one culture.
• How does cultural bias affect schizophrenia diagnosis?

  • Symptoms such as hearing voices with schizophrenia may have different meanings in different communities.
  • Haiti - some people believe voices are communication from ancestors.
  • There is an overinterpretation of symptoms in black British people (Escobar, 2012)
• Rosenhan (1973) Experiment - Aim


  To investigate whether psychiatrists actually manages to tease normal and abnormal psychological states apart.
• Rosenhan (1973) Experiment  - Sample


  • 9 particpants icnlusinf prof. Rosenhan, were recurited.All were deemed to have no present or past symptoms of serious psychiatric disorders.
  • Data from 12 hospital stays, at 12 different hospitals, by eight participants were included in the study. Five worked or were engaged in psychology or psychiatry.
• Rossenhan (1973) Experiment - Procedure

  1. Participants set up an appoinmet with a fake name,occupation and employment.
  2. At the appoinment they participants said they heard unclear voices which said 'hollow','empty' and 'thud'.
  3. On admittance, participants stopped simulating any psychiatric symptoms, though there were a few cases of “brief, mild nervousness and anxiety” which “abated rapidly.”
  4. The particpants told staff that they were fine and they no longer experienced symptoms andwere discharged when the hosiptal staff deemed them fit.