Schizophrenia - Classification and Diagnosis

Question 1

Implications of classification and diagnosis?

Answer 1

Misdiagnosis, Stigma, Advantages

Question 2

Misdiagnosis could lead to…

Answer 2

incorrect or no treatment, which will affect progress (recovery) and general outcomes

Question 3

Stigma could…

Answer 3

affect career (e.g. health questionnaires when applying, promotions), personal and social life

Question 4

Advantages of classification and diagnosis?

Answer 4

Determines treatment, information on implications/course of SZ, gives professionals a shared language

Question 5

Kendell and Jablensky?

Answer 5

Diagnostic categories are justifiable concepts and a useful framework for organising and explaining

Question 6

Reliability?

Answer 6

Refers to the consistency of a measuring instrument, such as the DSM

Question 7

How can reliability be measured?

Answer 7

Through inter-rater reliability or test-retest reliability

Question 8

Issues of reliability?

Answer 8

Low inter-rater reliability, unreliable symptoms, differences between the DSM and ICD

Question 9

Relationships between reliability and validity?

Answer 9

If it’s not reliable it can’t be valid - if psychologists can’t agree who has SZ (reliability) then what is it? (validity)

Question 10

Low inter-rater reliability?

Answer 10

There have been improvements but it remains an issue

Question 11

Researchers on low inter-rater reliability?

Answer 11

Beck BUT Carson BUT Whaley

Question 12

Beck?

Answer 12

Early versions of manuals weren’t very reliable as key terms weren’t clearly deigned and clinicians used different interview techniques

Question 13

Carson?

Answer 13

DSM-III has overcome problems described by Beck and has inter-rater reliability

Question 14

Whaley?

Answer 14

Found inter-rater reliability correlations as low as +0.11

Question 15

Implications of low inter-rater reliability?

Answer 15

Misdiagnosis and therefore stigma

Question 16

Issue with unreliable symptoms?

Answer 16

Some symptoms aren’t consistently identified by clinicians - they must be able to decide whether a symptom is present or not to make a diagnosis, but SZ is difficult to diagnose as there are no physical signs or definitive tests

Question 17

Researchers on unreliable symptoms?

Answer 17

Mojtabi and Nicholson

Question 18

Mojtabi and Nicholson?

Answer 18

Asked 50 senior psychiatrists in the US to differentiate between bizarre and non-bizarre symptoms and found IRR of +0.4

Question 19

DSMs and unreliable symptoms?

Answer 19

DSM-IV only requires 1 symptom if delusions are bizarre (the key symptom) BUT DSM V required 2 symptoms so no longer a problem

Question 20

Implications of unreliable symptoms?

Answer 20

While it’s no longer an issue it may’ve led to misdiagnosis in the past so may still be affecting individuals

Question 21

Issue with differences between the DSM and ICD?

Answer 21

Individuals should receive the same diagnosis from each if reliable

Question 22

What are the differences between the DSM and ICD?

Answer 22

More likely to be diagnosed with the ICD (requires 1 month of symptoms) than the DSM (1 month of symptoms + 6 months of disturbance/social occupational dysfunction)

Question 23

Researcher on differences between the DSM and ICD?

Answer 23

Copeland

Question 24

Copeland?

Answer 24

69% of 134 US psychologists (DSM) and 2% of 184 British ones (ICD) diagnosed SZ

Question 25

Implications of differences between the DSM and ICD?

Answer 25

Misdiagnosis or no diagnosis at all

Question 26

How are differences between the DSM and ICD being fixed?

Answer 26

Organisations such as WHO and APA have recognised the issue and have worked to produce the DSM V to improve reliability

Question 27

Issues of validity in classification and diagnosis?

Answer 27

Predictive validity, comorbidity

Question 28

What is validity?

Answer 28

The extent that a diagnosis represents something that’s real and distinct from other disorders, and the DSM and ICD measure what they claim to

Question 29

Issues with predictive validity?

Answer 29

If SZ is a valid disorder then patients should share the same outcomes and on that basis clinicians should be able to predict outcomes, but there are a lot of individual differences in response to treatment and outcomes

Question 30

Research on predictive validity?

Answer 30

Bentall et al

Question 31

Bentall et al?

Answer 31

20% of SZs responded to treatment and recovered previous levels of functioning, 10% achieved significant and lasting improvements, 30% some improvement with intermittent relapses

Question 32

What does Bentall’s research show?

Answer 32

SZ may not be a single unitary disorder so classification as a distinct disorder may not be valid

Question 33

Implications of predictive validity?

Answer 33

Brings into question one of the main aims of classification and diagnosis: deciding treatment - how clinically useful is C&D really?

Question 34

What is comorbidity?

Answer 34

The extent to which 2 conditions co-occur, e.g. SZ and substance abuse, anxiety etc.

Question 35

Research on comorbidity?

Answer 35

Buckley et al and Kessler et al

Question 36

Buckley et al?

Answer 36

Estimated comorbid depression in 50% of SZs and that 47% have a lifetime diagnosis of substance abuse

Question 37

Kessler et al?

Answer 37

National Comorbidity Survey - attempted suicide rate 1% for those with SZ alone, 40% of those with at least 1 lifetime comorbid disorder

Question 38

Issue with comorbidity?

Answer 38

It’s difficult to determine cause - is it SZ or a 2nd condition? If classification is valid the causes should be clear and the same for everyone

Question 39

Implications of comorbidity?

Answer 39

Which disorder should be focussed on? Therefore what treatment?