Schizophrenia Booklet 2: Reliability and validity in diagnosis

Question 1

What is a reliable diagnosis of SZ?

Answer 1

Where the instrument measuring SZ is consistent, so diagnosis one day will be the same the next day

Question 2

What is a valid diagnosis of SZ?

Answer 2

The extent to which the tools that measures SZ is measuring the mental disorder accurately

Question 3

How easy or difficult is it to achieve valid and reliable diagnosis?

Answer 3

Difficult to achieve as symptoms can be subjective and interpreted differently with health professionals. Which would create bias, reducing the reliability.

Question 4

What are the 7 named issues on the spec?

Answer 4

1. Validity
2. Concurrent validity
3. Co-morbidity validity
4. Inter-rate reliability
5. Symptom overlap
6. Culture bias
7. Gender bias

Question 5

What is the AO1 for issue of validity: validity?

Answer 5

-Validity is extent to which tool measuring SZ is measuring it accurately
-For example, making sure that the DSM and a doctor diagnose SZ in patients accurately and not another disorder

Question 6

What is the AO1 for issue of validity: Concurrent validity?

Answer 6

-This is extent to which a test to measure SZ concurs with an already existing current measure of SZ
-For example, the extent to which the DSM-5 and ICD-10 agree

Question 7

How would you phrase these AO1 paragraphs?

Answer 7

-“One issue surrounding the classification and diagnosis of SZ is validity. Validity is…”
-“Another issue surrounding the classification and diagnosis of SZ is concurrent validity. Concurrent validity is…”

Question 8

What is the AO1 for issue of validity: Co-morbidity validity?

Answer 8

-Where two conditions co-exist in same individual at same time, so SZ and something else
-Buckley 2009 found that 50% of people with SZ also have depression and 47% of people with SZ have substance abuse

Question 9

What is the AO1 for issue of reliability: reliability?

Answer 9

-this is where the instrument used to measure SZ is consistent
-For example, the extent to which a person is diagnosed with SZ is also diagnosed with SZ later that same day

Question 10

What is the AO1 for issue of reliability: inter-rater reliability?

Answer 10

-This is whether two independent assessors give the same diagnosis of sz to the same patient
-Nilsson 200 found that the inter-rater reliability for diagnosis of SZ 60%, meaning that there is a 40% likelihood that two different doctors will diagnose same patient with different disorders

Question 11

What is the AO1 for issue of: symptom overlap?

Answer 11

-this is where the symptoms for sz are also symptoms for another disorder, for example depression has similar symptoms to avolition

Question 12

What is the AO1 for issue of: culture bias?

Answer 12

-Culture can affect diagnoses and make them lack validity, this is because: -Drs use cultural norms to interpret patients
-Copeland 1971 gave a description of a patient to 134 US and UK clinicians. 69% of US diagnosed schiz but only 2% of UK, showing SZ is more likely diagnosed in US
-Also some cultures accept hallucinations as being normal

Question 13

What is the AO1 for issue of: Gender bias?

Answer 13

-People are more likely to be diagnosed with sz because of their gender, it has been suggested that men and woman are equally as vulnerable however men are 50% more likely to suffer from sz than women

Question 14

What is the AO3 of validity?

Answer 14

-Diagnosing someone means that we are labelling them and these labels can be difficult to remove. These may have long lasting negative effects, may affect jobs
-However, positive consequence of a valid diagnosis is it leads to proper treatment, if accurate diagnosis then valuable treatment such as meds, ability for more normal life

Question 15

What is the AO3 for concurrent validity?

Answer 15

-Diagnosis of SZ consequence is that Cheniaux 2009 found that patients more likely to be diagnosed with SZ when using ICD than the DSM, wrong diagnosis
-Diagnoses made by GPs are made against a background of previous patient knowledge and could be biased, for example, if the GP knows a patient has lost their job they may ignore symptom of avolition.

Question 16

What is the AO3 for CO-morbidity?

Answer 16

-It is difficult to know which is main disorder, might lead to misdiagnosis. SZ often occurs alongside disorders such as depression, hard for clinician to decide which main disorder is and which to treat.

Question 17

What should you write for the consequence of AO3?

Answer 17

This means that … can lead to an invalid/unreliable diagnosis of SZ

Question 18

What is the AO3 for inter-rater reliability?

Answer 18

-Very difficult for a patient to say the exact same thing on two differing occassions, clinician is relying on retrospective data when being interviewd, involves patients looking back on symptoms and may over-under exaggerate.

Question 19

What is the AO3 for symptom overlap?

Answer 19

-Doctor may be diagnosing the patient with wrong disorder, number of symptoms of sz are also symptoms of different disorders. Therefore clinician might diagnose a patient with SZ when suffering another disorder.

Question 20

What is the AO3 for cultural bias?

Answer 20

-A consequence with cultural bias in the diagnosis is that it may be influenced by the persons ethnic group or doctors culture, a patient may be diagnosed with SZ because of culture.
-Cochrane found that people of Afro-Caribbean origin are 7 times more likely to be diagnosed with sz when living in the uk.

Question 21

What is the AO3 for gender bias?

Answer 21

-A consequence is that women may be better able to mask their symptoms than men, Cotton found women more able to function between than men, as a result they may mask symptoms better at a doctors. This means that women may not be getting diagnosed with sz although they actually do suffer from it at the same rate as men.