Lesson 2 - Reliability Of Diagnosis

Question 1

What is test-retest reliability

Answer 1

It is when a psychiatrist makes the same diagnosis on 2 separate occasions from the same info

Question 2

What is inter-rater reliability

Answer 2

When 2 different psychiatrists agree on the same diagnosis when independently assessing the same patient

Question 3

What are the two diagnosis tools for Sz

Answer 3

DSM-5 - used in America - needs at least one positive symptom
ICD-10 - used internationally - can be based on negative symptoms alone

Question 4

ISSUE 1 - reliability of diagnosis
-Rosenham - sane in insane places

Answer 4

-8 sane confederates sent to psychiatric hospital and lied about hearing voices
-once admitted they started acting normal but still 7 diagnosed with Sz and 1 with manic depression
-35 real patients accused them of being sane
-showed psychiatrists cannot reliably tell insane from sane

Question 5

What is the follow up study to Rosenham’s - sane in insane places

Answer 5

-Rosenham warned hospital he would send more pseudo patients
-of 193 patients observed 21% were identified as fake but Rosenham never sent any pseudo patients
-further solidifies the lack of reliability

Question 6

ISSUE 2 - culture bias (validity and reliability)

Answer 6

-significant difference in diagnosis
E.g Caribbean origin more likely to be diagnosed. Hallucinations are more acceptable in African cultures because of ancestral communication = more likely to acknowledge

Question 7

ISSUE 2 - culture bias - Luhrmann

Answer 7

-60 Sz diagnosed interviewed
-20 from each Ghana, India and USA
- Each were asked about voices. African and Indian subjects reported positive experiences, describing them as playful or offering advice. Not one American did, they reported hateful and violent voices
- This means violent voices common in the west may not be inevitable feature of SZ
-symptoms should not depend on culture thus this challenges the reliability of the symptoms and the diagnosis

Question 8

Expand on this evaluation of reliability of diagnosis in Sz
-low kappa score rating

Answer 8

Rosenham - showed that psychiatrists cannot reliably tell the difference between sane and insane
-despite claims that the DSM has improved since the 70s, Whaley found poor inter-rather reliability for diagnosis with correlations as low as 0.11. This lowers reliability of diagnosis

Question 9

Expand on this evaluation of reliability of diagnosis in Sz
-poor inter-rater reliability

Answer 9

-what are the chances of 2 or more clinicians arriving at the same diagnosis for a patient - Cheniaux et al had 2 psychiatrists diagnose 100 patients using both DSM and ICD
- DSM - one diagnosed 26/100, other 13/100
- ICD - one 44/100 and other 24/100

Question 10

Expand on this evaluation of reliability of diagnosis in Sz
-subjectivity

Answer 10

-for Sz diagnosis, only one symptom is required if delusions are bizarre
-morjabi and Nicholson - 50 senior psychiatrists in the US were asked to differentiate non bizarre and bizarre delusions, produced 0.4 inter reliability