reliability and validity in diagnosis of schizophrenia Flashcards
1
Q
what is reliability?
A
- the extent to which a finding is consistent
- the extent to which psychiatrists can agree on the same diagnosis independently (inter-rater reliability)
- for a classification system to be reliable, the same diagnosis should be made each time
2
Q
what is validity?
A
- the extent we are measuring what we intend to measure
- consider the validity of the diagnostic tools: so different systems arrive at the same diagnosis for someone
3
Q
rosenhan (1973) - aim
A
- how situational factors affect a schizophrenia diagnosis
- sane confederates went to psychiatric hospitals saying they had hallucinations to assess if staff would detect their sanity or not
4
Q
rosenhan (1973) - method
A
- 8 confederates acted as pseudopatients and went to 12 different hospitals
- they called the hospital and asked for an appt, when they arrived they said they were hearing voices saying “empty”, “hollow” and “thud”
- when on the ward they stopped presenting symptoms and wrote observations
- they were discharged when staff believed they were sane
5
Q
rosenhan (1973) - results
A
- on admission staff diagnosed 11 with schizophrenia and one with manic depression. their sanity was never detected
- staff interpreted their behaviour in the context of their diagnosis
- the average stay was 19 days
- 35 real patients detected sanity
6
Q
rosenhan (1973) - conclusion
A
- staff cant always distinguish sanity from insanity, any methods that make these errors cant be reliable or valid
- but they may not identify santify as it’s less risky to diagnose a sane person as insane. so situational factors do affect diagnosis
- ‘normal’ behaviour was misinterpreted as ‘abnormal’ to support the diagnosis
- so the validity of diagnoses was low and the DSM was flawed
7
Q
co-morbidity
A
- more than one disorder existing alongside a primary diagnosis
- when 2 conditions are diagnosed together it questions the validity of each’s classification
- the findings of research may be due to psychiatrists not being able to tell the difference between the 2
- if severe depression looks like schizophrenia or vice versa they may be better as a single condition
8
Q
culture bias: variation between countries
A
- research suggests a significant variation between countries for diagnosis
- harrison et al: those of west indian origin were overdiagnosed by white doctors in bristol
- copeland et al: gave patient info to 134 US (69% diagnosed it) and 194 brit psychiatrists (2% diagnosed it). research has found no cause, suggesting the symptoms of minorities are misinterpreted
- questions the reliability of the diagnosis: patients can display the same symptoms but get different diagnoses due to their ethnicity
9
Q
culture bias: cultural differences
A
escobar: white psychiatrists may over-interpret the symptoms of black people during diagnosis, which may be due to cultural differences in language or mannerisms or the belief black people don’t suffer from affective disorders
10
Q
what is one issue with positive symptoms?
A
- hallucinations or hearing voices may be more acceptable in African cultures due to beliefs about communication with ancestors
- when reported to a psychiatrist from another culture this may be seen as bizarre as they are culturally biased to what is normal in their culture, so are ethnocentric
11
Q
gender bias
A
- critics argue some diagnosis categories are biased toward pathologising one gender over the other
- gender bias also occurs as clinicians don’t consider that men have more negative symptoms than women and have higher levels of substance abuse, or that women have better recovery and lower relapse rates.
- clinicians also ignore that there are different risk factors between men and women, giving them different vulnerability levels during their life
12
Q
broverman et al (1970) - androcentrism
A
- found US clinicians equated mentally healthy adult behaviour with that of men, showing androcentrism
- so women may be seen as less healthy when they don’t show male behaviour
13
Q
loring and powell (1988) - the effect of the clinician’s gender
A
- 290 male and female psychiatrists read 2 articles of a patients behaviour to give their judgement using standard criteria
- when described as male or no info on gender given, 56% were diagnosed, when described as female 20% were diagnosed
- this gender bias however wasn’t evident among female psychiatrists
14
Q
symptom overlap
A
- there is considerable overlap between the symptoms of schizophrenia and other conditions. e.g. schizophrenia and bipolar both share positive symptoms like delusions and negative symptoms like avolition. this questions the validity of the classification and diagnosis of schizophrenia
15
Q
ellason and ross (1955) - schizophrenia and bipolar overlap
A
- people with DID have more schizophrenic symptoms than those diagnosed with schizophrenia
- a person may be diagnosed as schizophrenic using the ICD but bipolar using the DSM. could suggest that schizophrenia and bipolar and one condition not two
