Diagnosis and classification

• Validity of schizophrenia - in the age of an illness like schizophrenia we have to consider the validity of the diagnostic tools; for example, do different assessment systems arrive at the same diagnosis for the same patient?
• Criteria is different for diagnostic manuals - this creates a problem
• DSM-V - diagnosis and statistical manual of mental illness (fifth edition) (American)

  • 5 sub-types
  • one or more POSITIVE symptoms must be present.
  • lasting 6 months
• also, there are different types of schizophrenia

  • disorganised
  • catatonic
  • paranoid

  this suggests that schizophrenia may be an umbrella term for many different disorders.
• reliability in schizophrenia is the extent to which psychiatrists can agree on the same diagnosis when independently assessing patients (inter-rather reliability)
• in order for a classification system to be reliable, the same diagnosis should be made each time. therefore different psychiatrists should reach the same decision when assessing a patient
• positive symptoms

  • an excess or distortion of normal functioning
  • hallucinations or delusions
• Negative symptoms

  • a reduction or loss of normal functioning
  • speech poverty
  • avolition
  • anhedonia
• • hallucinations= bizarre unreal perceptions of the environment. they are usually auditory but can be visual, olfactory or tactile.
• • delusions = bizarre beliefs that seem real but are actually not real - e.g. believing you are being spied on by someone.
• speech poverty = lessening of speech fluency and productivity . it can also be reflected in less complex syntax e.g. shorter utterances or fewer clauses.
• avolition = reduced interests, and an inability to persist in goal-directed behaviour. this is a reduction in self-initiated involvement in activities that are available to the patient e.g. social contact.
• • A weakness is that there is poor inter-rater reliability.
  • for example, Ellie Chemiaux (2009) had two psychiatrists independently diagnosed 100 patients using both the DSM and the ICD criteria, Inter-reliability was poor, with one psychiatrist diagnosing 26 according to the DSM and 44 according to the ICD. The other psychiatrist diagnosed 13 according to the DSM and 24 according to the ICD.
  • this poor reliability is a weakness of diagnosis of schizophrenia and shows the discrepancy between the two diagnostic manuals
• • Another weakness is co-morbidity.
  • Schizophrenia is often diagnosed with other conditions, for example Peter Buckley (2009) concluded that half of those who were diagnosed with schizophrenia also had a diagnosis of depression (50%) and 47% had substance abuse. Post-traumatic disorder also occurred in 29% of cases and OCD in 23%.
  • This poses questions on the classification and diagnosis of SZ and in terms of classification it may be just a severe case of depression rather than SZ.
• • Another weakness is gender bias.
  • Julia Longenecker (2010) reviewed studies and found that since the 1980s, men have been diagnosed more often than women.
  • it appears that female patients function better than males and are more likely to work and have good family relationships (Cotton 2009). This high functioning means that they are able to mask the symptoms and because of good interpersonal functioning makes. The case too mild for diagnosis.
  • This suggests women are undiagnosed more often than men due to symptom masking causing a gender bias.