Schizophrenia: Reliability & Validity in diagnosis

Question 1

What is the definition for diagnosis?

Answer 1

The identification of the nature of an illness or other problems by examination of the symptoms
Like someone reporting hearing voices

Question 2

What is the definition of classification?

Answer 2

The act of classifying something, the classification of disease according to symptoms
Like a symptom of Sz is hallucinations

Question 3

What does reliability refer to?

Answer 3

Consistency

Question 4

What is reliability?

Answer 4

Whether we can gain consistnecy reuslts when classifying and diagnosing Sz.

Question 5

What is reliability measured by?

Answer 5

Inter-rater reliability

Question 6

Different classification systems and reliabilty

Answer 6

The extent to which different classification systems agree upon how Sz should be classified

Question 7

Health professions and diagnosis

Answer 7

The extent to which two or more health professions would agree on the same diagnosis.

Question 8

What does validity refer to?

Answer 8

Accuracy

Question 9

What is validity?

Answer 9

The extent to which we are measuring what we intend to measure

Question 10

What is an example of validity and Sz?

Answer 10

Are the classification systems accurately outlining the signs and symptoms of Sz and are health professions accuratley diagnosing Sz?

Question 11

Who investigated the validity and reliability of the classification systems?

Answer 11

Cheniaux

Question 12

What did Cheniaux do?

Answer 12

Asked two psychiatrists to diagnose the same 100 patients using the DSM and ICD

Question 13

What did the psychiatrists diagnose?

Answer 13

One diagnosed 26 according to DSM and 44 according to ICD
The other diagnosed 13 according to DSM and 24 according to ICD

Question 14

What did the findings show?

Answer 14

Poor inter-rater reliability as one psychiatrist diagnosed almost double the amount than the other.

Question 15

What else does it show?

Answer 15

Poor reliability in the classification of Sz as both psychiatrists diagnosed almost double the number of patients using ICD than DSM, calls into question the validity of the diagnosis.

Question 16

What is symptom overlap?

Answer 16

Where two or more conditions share similar symptoms

Question 17

What is an example of symptom overlap?

Answer 17

Sz and depression involve negative symptoms such as avolition

Question 18

What is co-morbidity?

Answer 18

Where two illnesses/conditions occur at the same time

Question 19

What is an example of co-morbidity?

Answer 19

Sz is commonly diagnosed with depression and/or OCD as they share common symptoms

Question 20

What could co-morbidity lead to?

Answer 20

Misdiagnosis

Question 21

What is the link between gender and Sz?

Answer 21

Since 1980s, men have been diagnosed with Sz more often than women

Question 22

Why do men get diagnosed with Sz more often than women?

Answer 22

Men are more genetically vulnerable then women

Question 23

Why are women less likely to be diagnosed with Sz?

Answer 23

Women with Sz typically function bettwe than men
More likely to work and have good family relationships.

Question 24

What is the link between culture and Sz?

Answer 24

English people of African origin are more likely to be diagnosed with Sz in UK.

Question 25

Why are there higher rates in the UK for english people of African origin?

Answer 25

Some behaviours classed as positive symptoms of Sz are normal in African cultures E.g., hearing voices as part of ancestor communciation

Question 26

What is one problem with the reliability and validity of classification and diagnosis of Sz

Answer 26

Often there’s system overlap
Say what system overlap is
Questions the validitiy and reliability of classification and diagnosis of Sz because an individual may be diagnosed with wrong disorder. If not diagnosed properly, won’t get proper treatment.
Weakens validity and reliability - negatively affects accuracy and consistency

Question 27

Another problem

Answer 27

Co-morbidity
Say what it is
E.g., Buckley et al concluded that 50% of patients with Sz also have a diagnosis of depression and 23% are diagnosed with OCD. Questions validity and reliability as two conditions may be better seen as one and may diagnose the wrong ones, results in inappropriate treatment

Question 28

Another issue

Answer 28

Gender bias
Say AO1 gender bias
Questions validity and reliability, women who share similar symptoms as en may not receive the same diagnosis as their symptoms seem mild.