Diagnosis

• Reliability

  can be assessed in two ways

  • inter rater reliability - the agreement between clinicians regarding the same diagnosis of a patient
  • test retest - where the same clinician assesses the same patient on separate occassions
• A strength of the diagnosis is its reliability.

  • prior to DSMV the reliaibility was low

  Research from Osorio et al suggests it has improved - 180 schizophrenic patients were assessed. Pairs of interviews had an inter rater reliability of +.97 and a test retest rate of +.92.

  This shows consistency in diagnosis
• Validity - whether we are measuring what we intend to measure

  • compare the use of DSM and ICD at the same time with the same patient/s
• Validity

  
  

  Chaniaux et al studied 2 psychiatrists who independently assessed the same 100 clients using the DSMIV and ICD10

  • 68 diagnosed using ICD10 and 39 using DSMIV
  • means that the diagnostic tools could be over or under diagnosed dependeing on the system used
  • questions the validity as they did not come close with the number of patients diagnosed
• Symptom overlap is when the symptoms of a disorder overlap with symptoms of another disorder.

  • schizophrenia can be hard to distinguish from bi polar disorder
  • both involve positive and negative symptoms such as avolition
  • this means they may not be separate conditions, but instead, a variation of the same condition
  • therefore both the diagnosis and classification are flawed
• Co-morbidity - two conditions occuring at the same time.

  Research shows that schizophrenia occurs alongside depression 50% of the time and 47% of the time alongside substance misuse.

  This is a problem for classification as it may not exist as a distinct condition.
• Culture bias- ethnic minorities are misrepresented.

  • British Afro-Carribeans are more likely to be diagnosed than British whites (up to 9 times)
  • This suggests bias when diagnosing people of another background which can lead to discrimination
  • Hallucinations are also seen as more acceptable in Africa or Haiti because of cultural beliefs about communication with ancestors whereas in western culture, they may be seen as irrational
• Gender bias - the ratio of males and females diagnoised is 1.4 : 1

  • critics of the DSM diagnostic criteria argue that some categories are biased towards pathologising one gender rather than the other
  • one suggestion is that women are under diagnosed as they have closer relationships and get more support, so women cope better
• Rosenhan - Procedure

  • between 1969 and 1972 Rosenhan sent 8 pseudopatients to 12 psychiatric wards in USA who pretended to hear voices saying "empty, hollow, thud"
  • 12 psychiatric hospitals across 5 states
  • Ps are the staff and other patients
  • DSM II used at the time
• Rosenhan - Findings

  • All were admitted into hospitals, and once there, when they stopped having the symptom, said they were fine and could be released
  • Responses of the staff were noted and the experience of being hospitalised was recorded
  • All but one were diagnosed
  • The other was diagnosed with Bipolar
  • Released between 7-52 days
  • Mean stay length of 19 days
  • Released with diagnosis in remission
  • 35/118 patients accused pseudopatients of not actually being ill
• Follow up study - Rosenhan

  • hospitals were told to expect pseudopatients
  • in reality, none were sent
  • from 193 admission, 41 were rated as pseudopatients by at least one member of staff
  • 23 were rated by at least one psychiatrist
  • 19 were rated by both