Sc - Reliability and validity in diagnosis and classification Flashcards

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1
Q

Co-morbidity

A

Refers to the extent that two (or more) conditions or diseases occur simultaneously in a patient, for example sz and depression.

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2
Q

Culture

A

The rules, customs, morals, childrearing practices, etc. that bind a group of people together and define how they are likely to behave.

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3
Q

Gender bias

A

Refers to the tendency to describe the behaviour of men and women in psychological theory and research in such a way that might not be seen to represent accurately the characteristics of either one of these genders.

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4
Q

Reliability

A

Is consistency - the consistency of measurements. We would expect any measurement to produce the same data if taken on successive occasions.

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5
Q

Symptom overlap

A

Refers to the fact that symptoms of a disorder may not be unique to that disorder but may also be found in other disorders, making accurate diagnosis difficult.

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6
Q

Validity

A

Refers to whether an observed effect is a genuine one.

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7
Q

What does diagnostic reliability mean in sz?

A

Means that the diagnosis of sz must be repeatable, i.e. clinicians must be able to reach the same conclusions at two different points in time (test-retest reliability), or different clinicians must reach the same conclusions (inter-rater reliability).

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8
Q

What is test-retest reliability?

A

Clinicians must be able to reach the same conclusions at two different points in time.

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9
Q

What is inter-rater reliability?

A

Different clinicians must reach the same conclusions.

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10
Q

What is inter-rater reliability measured by?

A

A statistic called a kappa score.

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11
Q

Explain how kappa scores work

A

Used to measure inter-rater reliability.

A score of 1 indicates perfect inter-rater agreement; a score of 0 indicates zero agreement.

A kappa score of 0.7 or above is generally considered good.

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12
Q

What is the kappa score for the diagnosis of SZ in the DSM-V field trials?

A

0.46 (Regier et al., 2013).

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13
Q

What factor is talked about when discussing the reliability of classification/diagnosis?

A

Cultural differences.

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14
Q

What factors are talked about when discussing the validity of classification/diagnosis?

A

Gender bias, symptom overlap and co-morbidity.

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15
Q

Explain how there is cultural bias in diagnosis of SZ

A
  • Copeland (1971) gave 134 US and 194 British psychiatrists a description of a patient. 69% of the US psychiatrists diagnosed SZ, but only 2% of the British ones gave the same diagnosis.
  • ‘Hearing voices’ as a symptom appears to be influenced by cultural environment - Luhrmann et al. (2015) interviewed 60 adults with SZ (20 each in Ghana, India and the US). Each was asked about the voices they heard - many of the African and Indian subjects reported positive experiences with their voices (describing them as playful or as offering advice) but none of the Americans did. The US subjects were more likely to report them as violent and hateful (and indicative of being ‘sick’). Luhrmann suggests that the ‘harsh, violent voices so common in the West may not be an inevitable feature of SZ’.
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16
Q

Explain how there is gender bias in diagnosis of SZ

A
  • Said to occur when the accuracy of diagnosis is dependent on the gender of an individual.
  • The accuracy of diagnostic judgements can vary for a number of reasons, including gender-biased diagnostic criteria or clinicians basing their judgements on stereotypical beliefs held about gender.
  • For example, critics of the DSM diagnostic criteria argue that some categories are biased towards pathologising one gender rather than the other.
  • Broverman et al. (1970) found that clinicians in the US equated mentally healthy ‘adult’ behaviour with mentally healthy ‘male’ behaviour. As a result, there was tendency for women to be perceived as less mentally healthy.
17
Q

Explain how symptom overlap affects the validity of SZ diagnosis/classification

A
  • Many positive and negative symptoms of SZ are also found in many different disorders, such as depression and bipolar disorder.
  • Ellason and Ross (1995) point out that people with dissociative identity disorder (DID) actually have more schizophrenic symptoms than people diagnosed as being schizophrenic!
  • Most people who are diagnosed with SZ have sufficient symptoms of other disorders that they could also receive at least one other diagnosis (Read, 2004).
18
Q

Explain how co-morbidity affects the validity of SZ diagnosis/classification

A
  • Including substance abuse, anxiety and symptoms of depression,
  • Buckley et al. (2009) estimate that co-morbid depression occurs in 50% of patients, and 47% of patients also have a lifetime diagnosis of co-morbid substance abuse.
  • SZ and OCD are 2 distinct psychiatric conditions. Roughly 1% of the population develop SZ, and roughly 2-3% develop OCD. Despite both being fairly uncommon, evidence suggests that the two conditions appear together more often than chance would suggest. A meta-analysis by Swets et al. (2014) found that at least 12% of patients with SZ also fulfilled the diagnostic criteria for OCD and about 25% displayed significant obsessive-compulsive symptoms.
19
Q

What is the key study for the reliability and validity in diagnosis and classification of SZ?

A

On being sane in insane places.

20
Q

What did the on being sane in insane places study highlight?

A

The unreliability of diagnosis.

21
Q

Who did the on being sane in insane places study?

A

Rosenhan (1973)

22
Q

Explain the on being sane in insane places study

A

‘Normal’ people presented themselves to psychiatric hospitals in the US claiming they heard an unfamiliar voice in their head saying the words ‘empty’, ‘hollow’ and ‘thud’.

They were all diagnosed as having SZ and admitted. Throughout their stay, none of the staff recognised that they were not actually displaying symptoms of SZ.

In a follow-up study, Rosenhan warned hospitals of his intention to send out more ‘pseudopatients’. This resulted in a 21% detection rate, although non actually presented themselves!