Evaluation

• Reliable measures


  • Consistent diagnosis across time and clinicians
  • Inter-rater and test-retest reliability - Kappa score of 1 = perfect
  • Osorio - DSM-5;
  • IR - +0.97
  • TR - +0.92
  • Improvement from DSM-3; +0.11 (Whaley)
• Valid measures


  • Accurate and distinct diagnosis
  • Criterion validity - different established measures
  • Cheniaux - 68/100 schizophrenics diagnosed with ICD-10, 39/100 with DSM-4
  • Low validity
  • Diagnostic stability; DSM-5 - .9
  • Comparable to dementia - fixed validity issues
• Co-morbidity


  • Validity is made difficult by comorbidity - SZ occurs alongside other disorders, such as depression
  • Buckley - 50% of patients diagnosed with SZ also have depression, 47% have substance abuse
  • Therefore, challenges validity of diagnosis
• Symptom overlap


  • SZ and bipolar both share similar symptoms
  • Ketter - misdiagnoses can lead to years of delay in receiving treatment
  • Serious consequences - high suicide rates
  • Serper et al. - SZ and cocaine abuse - although symptoms overlapped it was possible to make accurate diagnoses due to clinician expertise
  • Therefore, symptom overlap may not affect validity too badly
• Gender bias


  • Fischer and Buchanan - men more likely to receive SZ diagnosis (1.4:1)
  • Males tend to have more negative symptoms, higher levels of substance abuse, females have better recovery rates and more likely to maintain relationships
  • Beta bias - clinicians may look for 'male' symptoms, ignoring 'female' ones
  • Loring and Powell - 290 male and female psychiatrists
  • When 'male' or not specified, 56% diagnosed, when 'female', 20%
  • Not evident amongst female psychiatrists - gender bias in clinician and patient
• Culture bias


  • Escobar - white psychiatrists overinterpret symptoms of black people during diagnosis e.g. language and mannerisms
  • Harris et al. - West Indians overdiagnosed with SZ by white doctors in Bristol
  • DSM-5 cultural considerations, problems still persist
  • Certain symptoms more acceptable in certain cultures - hallucinations - unknowingly ethnocentric
  • 'Bizarre' - different meanings
  • Ethnic people more likely to talk about experiences