Classification + Diagnosis of Schizophrenia

Reliability
1. A01
  1. Refers to consistency of measuring instrument, such as a questionnaire or scale, to assess, for example, severity of their Sz symptoms
    1. R can be measured in terms of whether 2 independent assessors give similar diagnosis (inter-rater r) or whether tests used to deliver these diagnosis are consistent over time (test-retest r)
2. A02
  1. Unreliable sympotms
    1. To be diagnosed w/ Sz, a person only has to have 1 of characteristic sympotms if their 'delusions are bizarre'
      1. Mojtabi + Nicholson
        50 senior US psychiatrists were asked to differentiate between 'bizarre' + 'non-bizarre' delusions
        They produce inter-reliability correlations of only around +40, forcing researchers to conclude even this central diagnostic requirement lacks sufficient reliability for it to be reliable method of distinguishing between Sz + non-Sz patients
  2. Cultural differences in diagnosis
    1. Copeland
      1. Gave 134 US + 194 British psychiatrists a description of a patient
        69% of US psychiatrists diagnosed Sz but only 2% of British psychiatrists gave same diagnosis
Reliability - Rosenhan
1. A01
  1. Situational factors are supposedly more important than actual characteristics of a person when it comes to diagnosis
2. A02
  1. Demonstrated effect of 'situational' factors in study 'being sane in insane places'
    1. Pseudo patients were sent into institutions + were classified as Sz
      1. Claimed they heard an unfamiliar voice saying words 'empty', 'hollow' + 'thud'
    2. Throughout stay, none of the staff recognised they were actually normal
      1. Some of them made notes of what was occurring while omitted - staff took this as part of their Sz
        Suggests situation is more important than actual person
  2. Complication made more apparent...
    1. Follow-up study
      1. R warned hospitals of his intention to send out more 'pseudo patients'
        Resulted in 21% detection rate
        Although none actually presented themselves
Validity
1. A01
  1. Refers to extent a diagnosis represents something that is real + distinct from other disrders
    1. + extent a classification system (ICD or DSM) measures what it claims to measure
  2. R + V inextricably linked because diagnosis cannot be valid if it isn't reliable
2. A02
  1. Comorbidity
    1. Refers to extent two (or more) conditions co-occur
      1. Commonly found among patients diagnosed w/ Sz
    2. Medical complications
      1. Poor levels of functioning found in many Sz may be less result of psychiatric disorder + more to do w/ untreated comorbid physical disorders
      2. Weber et al
        Examined nearly 6 million hospital discharge records
        Psychiatric + behaviour related diagnosis accounted for 45% of C
        Many patients w/ primary diagnosis of Sz also diagnosed w/ med probs. - asthma, hypertension + type 2 diabetes
        Concluded consequence of being diagnosed w/ psychiatric disorder such as Sz is patients tend to receive lower standard of med care, which in adversely affects prognosis
        Also found evidence of many comorbid non-psychiatric diagnoses
    3. Suicide risk
      1. People w/ Sz pose relatively high risk for S, w/ comorbid depression being major cause for suicidal behaviour
        Among patients in National Comorbidity Survey, rate for attempted suicide rose from 1% of those w/ Sz alone to 40% for those w/ at least 1 lifetime comorbid mood disorder
Predictive validity
1. A01
  1. People diagnosed as Sz rarely share same symptoms, nor is there evidence they share same outcomes
    1. Prognosis for patients varies w/ about 20% recovering their previous level of functioning, 10% achieving significant + lasting improvement + about 30% showing some improvement w/ intermittent relapses
      1. Diagnosis of Sz, therefore, has little PV - some people never appear to recover from disorder, but many do
2. A02
  1. Symptoms
    1. Despite belief identification of symptoms of Sz would make for more valid diagnoses of disorder, many symptoms also found in other disorders
    2. Ellason + Ross
      1. People w/ dissociative identity disorder (DID) actually have more Sz symptoms than people diagnosed as being Sz!
  2. Other factors linked to prognosis of disorder
    1. Gender, ethnicity + psychosocial factors
      1. M are supposedly more at risk than w
      2. Harrison et al
        Reported incidence rate for Sz was 8 times higher for African-Caribbean groups than for white groups
        Result of poor housing, higher rates of unemployment + social isolation
        Or result of cultural differences in language + mannerisms + difficulties in relating between black patients + white clinicians

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Classification + Diagnosis of Schizophrenia

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	Created by bebe97 about 9 years ago