RELIABILITY/VALIDITY IN THE DIAGNOSIS + CLASSIFICATION OF SZ

Schizophrenia is diagnosed using the DSM-5 and ICD-10

LIMITED RESEARCH TO SUPPORT THE RELIABILITY OF THE DIAGNOSIS OF SCHIZOPHRENIA - CHENIAUX (2009)

If the methods used for classifying + diagnosing schizophrenia are not reliable/valid it can cause major issues with treatment being unreliable along with invalid assessment will then lead to ineffective treatment

It is used to measure the severity of a patients symptom and assess their response to treatment

Diagnosis of schizophrenia must be repeatable - Theres two main types of reliability that have been investigated

Test-retest reliability - presenting participants with the same test at different points in time to see if there's a positive correlation which will demonstrate that the assessment criteria used are consistent

Inter-rater reliability - this is the idea of whether different clinicians reach the same conclusion

  • Cheniaux investigated inter-rater reliability of the DSM + ICD
  • 2 psychiatrists assess 100 patients using DSM + ICD and found poor inter-rater reliability
  • 1 psychiatrist diagnosed 26 patients using DSM + 44 using ICD
  • This shows that Sz is over or under diagnosed using different systems
  • Further supported by Reiger (2013) - found a DSM-5 Kappa score or 0.46 which indicates poor inter-rater reliability + highlights a weakness of diagnosis of Sz

MAJOR LIMITATION - BUCKLEY - FOUND THAT CO-MORBID DEPRESSION OCCURS IN 50% OF SZ PATIENTS

  • Maybe we are bad at telling the difference between the 2 conditions
  • Or maybe they are similar they might be between seen as a single condition
  • This confusing picture is a weakness in the classification of Sz

Co-morbidity

  • Refers to the extent that 2 (or more) conditions co-occur
  • If conditions occur together a lot of the time it calls into question the validity of their diagnosis because they might actually be a single condition
  • Co-morbidities are common with schizophrenics, e.g. depression + OCD

Gender bias

  • Powell - found that when 290 male + female psychiatrists were provided with 2 case studies of a patient behaviours 56% were diagnosed when described as 'males'+ only 20% were diagnosed when described as 'females'
  • However, there was no evidence of gender bias present with female psychiatrists. This shows that the gender of the patient + psychiatrists is clearly a factor when diagnosing the disorder
  • Diagnosis of Sz is dependent on the gender of the patient which could be in regards to a gender biased criteria or when clinician base judgements on stereotypical beliefs

CULTURAL BIAS - COPELAND

Cultural bias

  • Individuals of African American/Caribbean origin are several times more likely than white people to be diagnosed with Sz
  • However, Sz rates in Africa + West Indies are not high which suggests that it can't be due to genetic vulnerability
  • The positive symptoms e.g. hallucinations are more acceptable in African cultures, However, when these are reported in a different culture it is seen as bizarre/irrational
  • Other researchers have gone as far to suggest that white psychiatrists distrust the honesty of black people during diagnosis
  • Found that different countries + cultures have differences in diagnosis
  • When 200 US + UK psychiatrists were given a description of a patient, 69% US psychiatrists diagnosed the patient with Sz, However only 2% of UK psychiatrists did
  • This highlights the cultural bias evident in the diagnoses of Sz

GENDER BIAS - LONGNECKER

  • 1980 men are more often diagnosed than women
  • His explanation was that either men are genetically more vulnerable or it is a result of gender bias e.g. women function better than males with the disorder + are more likely to ork better in relationships
  • This highlights that the diagnosis of the disorder is potentially subject to gender bias