Validity of classification systems Flashcards
What are the 4 types of validity?
Internal
Predictive
Concurrent
Construct
What is the clinical psychology definition of ‘internal validity’? (2 points)
The extent to which psychologists are measuring what they intend to measure
Establishing cause and effect between the symptoms and behaviours exhibited by the patient and the clinical diagnosis
What is the clinical psychology definition of ‘predictive validity’? (2 points)
When the expected result matches the actual result when using a test
Eg. the psychologist’s initial formulation and diagnosis matches the symptoms of the clinical condition
What is the clinical psychology definition of ‘concurrent validity’? (2 points)
When two tests conducted at the same time focusing on the same clinical condition produce the same results
Useful when comparing a new psychological test with an existing established test, to ensure new techniques are in line
What is the clinical psychology definition of ‘construct validity’? (2 points)
How far the constructs (for example, symptoms) that are being measured represent the mental disorder
For example, for a person diagnosed with depression, how well the number of days absent from work were represents their clinical condition
What are the 4 pieces of supporting evidence and 4 pieces of refuting evidence for the validity of classification systems?
Supporting:
Internal: Beck et al (1996)
Predictive: Keenan et al (2010)
Concurrent: Kendler (1980)
Construct: Robins and Guze (2006)
Refuting:
R.D Laing (1960)
DSM revisions ‘gagging order’
Overmedicalisation of DSM-V
Belluck (2013)
How does Beck et al support the internal validity of classification systems? (3 points)
Objective measurement scales with operationalised variables are used to measure symptoms and behaviours
E.g. Beck’s Depression Inventory
+ Measures core symptoms of depression summing up to a depression score
+ Cause and effect can be established between a patient’s symptoms and self-report scale
Alows a suitable diagnosis to be made and treatment plans identified
How does Keenan et al support the predictive validity of classification systems? (2 points)
Results showed good predictive validity for 124 twins aged 3-5 years old with Oppositional Defiant (ODD) and Conduct Disorders (CD)
Preschoolers met the criteria for the same disorder during a follow-up:
+ 80% of those diagnosed with ODD
+ 60% of those diagnosed with CD
How does Kendler support the concurrent validity of classification systems? (2 points)
He further distinguished types of validators such as:
+ Concurrent validators (psychological tests)
+ Predictive validators (response to treatment, rate of relapse)
This distinction enabled Delusional Disorder to be classified as a disorder different from Sz
How do Robins and Guze support the construct validity of classification systems? (3 points)
They proposed 5 formal criteria for establishing the validity of clinical diagnosis
Found that ‘good prognosis Sz’ is not mild Sz but a different illness altogether
This led to the distinction between schizophrenia and schizophreniform disorder listed in the DSM-3
What are the 5 formal criteria for the validity of clinical diagnosis that Robins and Guze proposed?
- Clinical description
- Laboratory studies
- Delimitation from other disorders
- Follow-up studies
- Family studies
How does R.D Laing refute the validity of classification systems? (3 points)
Suggested that schizophrenia is just another way of living and not a clinical condition
He set up the Rumpus Room experiment in 1955:
+ After 18 months in the new environment, all 12 patients had improved enough to be discharged
+ They were back in hospital a year later
Critics argued this demonstrated schizophrenia was a lifelong condition - could only be marginally improved by environment
How does the DSM revisions ‘gagging order’ refute the validity of classification systems? (3 points)
Out of 160+ in the DSM Task Force, only 47 were psychologists and 100 were medically trained psychiatrists
Lack of transparency has been cited as an issue - agreements were put in place that no one was able to talk about the review process of DSM 5 during its development
This ‘gagging order’ has reduced its credibility
How does the overmedicalisation of the DSM-V refute the validity of classification systems? (3 points)
DSM is criticised for ‘medicalising’ mental illness where ‘patients’ are ‘treated’ with ‘medication’ for a ‘disorder’
It is argued that the diagnosis should fit the patient, but the DSM-5 tries to make the patient fit the diagnosis.
Over-medicalisation of the DSM-5 could result in more Type I errors
How does Belluck refute the validity of classification systems? (2 points)
Stated that the DSM-5 revisions (the data collected over the past 10 years) fails to account for neuroscience and biology
The DSM-5 lacks the level of specificity and sensitivity in its diagnostic criteria that would allow it to be more valid
