Intro to schizo:

• LIMITATION:

  • its validity
  • In general validity concerns whether we assess what we are trying to assess
  • One way to assess validity of a psychiatric diagnosis is criterion validity.
  • Cheniaux et al had two psychiatrists independently assess the same 100 clients using ICD-10 and DSM-5 criteria and found that 68 were diagnosed with schizophrenia under the ICD system and 39 under DSM

  This suggests that schizophrenia is either over- or underdiagnosed according to the diagnostic system.

  Either way this suggests that criterion validity is low.
• COUNTERPOINT:

  • In the Osório et al. study reported above there was excellent agreement between clinicians when they used two measures to diagnose schizophrenia both derived from the DSM system.

  This means that the criterion validity for diagnosing schizophrenia is actually good provided it takes place within a single diagnostic system.
• X

  • co-morbidity with other conditions
  • If conditions occur together a lot of the time then this calls into question the validity of their diagnosis and classification as they might be a single condition
  • Schizo is commonly diagnosed with other conditions
  • IE Review found that about half of those diagnosed with schizophrenia also had a diagnosis of depression or substance abuse Buckley et al

  Classification as schizo may not exist as a distinct condition

  Problem for diagnosis as at least some people diagnosed with schizo may have unusual cases of conditions like depression