Reliability and Validity in diganosis and classification

Question 1

define reliability

Answer 1

consistency of a classification system to assess particular symptoms of schizophrenia

Question 2

define validity

Answer 2

the extent that a diagnosis represents something real and distinct from other orders

Question 3

diagnostic reliability

Answer 3

• schiz diagnoses must be repeatable
• two clinicians able to reach the same conclusions using inter-rater reliability

Question 4

cultural difference in diagnosis

Answer 4

• some symptoms e.g. hearing voices considered normal in diff cultures
• hearing voices influenced by environment - e.g. us describe voices as harmful, but african/indian describe positive experiences

Question 5

gender bias

Answer 5

• accuracy of diagnosis dependent on the gender of the individual
• women may be perceived as less mentally healthy or stable

Question 6

symptom overlap

Answer 6

• many schiz symptoms found in other disorders e.g. bipolar
• can lead to misdiagnosis

Question 7

co-morbidity

Answer 7

• the extent that two or more conditions co-occur
• common in those who suffer from schiz
• include substance abuse, anxiety, and depression
• Buckley at al (2010): 50% of those suffering with schiz suffer with co-morbid depression.

Question 8

limitations 1: reliability and validity

Answer 8

Lacks reliability from professionals
- Cheniaux et al.
- subjective judgement on classification and diagnosis
DSM and ICD lack validity
- differences in diagnosis rates between the two
- under/overdiagnosis, ppts have incorrect or delayed treatment

Question 9

limitation 2:

Answer 9

Unreliable symptoms
- i-rr +0.4 for 50 us psychs classifying bizarre delusions
- nedded for diagnosis on dsm and icd, psych struggle to agree, misdiagnosis

Question 10

Cheniaux et al

Answer 10

• 2 psychiatrists asked to diagnose 100 patients using dsm and icd
• 1st psychiatrist: 26 w/ dsm, 44/ icd
• 2nd psychiatrists:13 w/dsm, 24 with icd