Week 1 Chapter 3 - DN (incomplete) Flashcards
Learning Goal 1.
Describe the purposes of diagnosis & assessment
Diagnosis
- enables accurate communication between clinicians about cases & scientists about research
- important for research on causes & treatments
Assessment
- helps make a diagnosis
- provides information beyond the diagnosis
p.63
Learning Goal 2.
Distinguish the different types of reliability & validity
Reliability - Consistency of measurement
- Internal Consistency reliability
- Interrater reliability
- Test-retest reliability
- Alternate-form reliabiltiy
Validity - degree to which an instrument measures what it is supposed to measure
- Content validity - how well test items relate to domain of interest
-
Criterion validity - compared current measure to some other measure in an expected way
- Concurrent validity - measured at same time
- Predictive validity - future measurement
-
Construct validity - *theory related - compares particular attribute with existing data (or theory) of the same construct (e.g., anxiety) *
- Convergent validity - data aligns with existing as expected
- Divergent validity - data differs from existing as expected
Learning Goal 3.
Identify the basic features, historical changes, strengths & weaknesses of the DSM
Learning Goal 4.
Describe the goals, strengths, weaknesses of psychological & neurobiological approaches to assessment
Learning Goal 5.
Discuss ways culture & ethnicity impact diagnosis & assessment
What important concepts play a key role in diagnosis & assessment?
- Reliability
- Validity
p.63-64
How does the focus of Reliability differ to that of Validity?
-
Reliability
- group of scores (are they consistent or repeatable)
-
Validity
- the test (does it measure what it says it measures)
Describe the relationship between Reliability & Validity?
- a measure with poor reliability will also have poor validity
- as an unreliable measure is inconsistent, it will not relate strongly to other measures (i.e., as required in construct validity (convergent/divergent)
on the other hand
-
good reliability does not guarantee good validity
- (i.e., a measure could be consistently innacurate)
p.64
Contrast convergent validity and discriminant validity? What are both of these used for?
- Both are indicators of Construct validity which is ‘theory related’ (i.e., data from a new instrument/measure is compared to that of an existing instrument/measure)
-
Convergent validity shows a relationship where one is expected
- (based on existing theory/evidence)
-
Discriminant validity shows little/no relationship where little/no relationship is expected
- (again based on existing theory/evidence)
-
Convergent validity shows a relationship where one is expected
How do Construct validity & Criterion validity differ?
Construct validity
- a test is evaluated against a wide variety of data
- multiple sources
**Criterion validity **
- a test is evaluated against one piece of data
p. 65
What has DSM-IV-TR’s, Axis V (Global Assessment of Functioning Scale GAF) been replaced with in the new DSM-5?
- Rating scales of severity along a continuum (specific to each disorder)
p. 69
Why does the DSM-5 continue to use symptoms as the basis for disgnosis?
- Our knowledge base is not yet strong enough to make diagnoses based on etiology
- No laboratory tests, neurobiological markers or genetic indicators are yet available for use in diagnosis
p.69
Give an example of one way DSM-5 reflects our growing knowledge of etiology/comorditiy?
OCD has been moved from the Anxiety disorder grouping and a new chapter has been introduced including:
- Obsessive-compulsive disorder
- Hoarding disorder
- Body dysmorphic disorder
This was done based on etiology seeming to involve distinct genetic & neural influences (differing to other anxiety disorders)
p. 69
What are the broad changes in DSM-5
- Changes to Multiaxial System
- Organising Diagnoses by Causes
- Inclusion of Continuous Severity Rating (supplementing Categorical Classification)
- Changes in Personality Disorder Diagnoses
- New Diagnoses
- Combining DSM-IV-TR Diagnoses
- Clearer Criteria
- Ethinic & Cultural Considerations in Diagnoses
p.69-73
How has the Muliaxial system changed in the DSM-5?
- 5 axes of DSM-IV-TR are reduced to one for psychosocial & environmental problems
- Codes for this axis have changed to be more similar to ICD
- International Classification of Diseases (World Health Organisation)
- Axis V removed
- instead severity scale developed for each disorder
p.69
How does a dimensional system of diagnosis differ to a categorical classification system?
Which of these systems is used in the DSM-5?
- A dimensional system describes the degree of an entity that is present
- (e.g., 1-to-10 of anxiety, 1 represents minimum & 10 the extreme)
- A classification system - considers presence or absence of a condition
- it does not consider continuity between typical - atypical behaviour
- DSM-5 incorporates the dimensional system but has also preserved the categorical approach to diagnosis
- i.e., the categories are supplemented by a severity rating for each disorder
p.71
Why are categorical systems so popular?
- the cut-offs provide a threshold (although arbitrary)
- offering doctors guidance for treatment
p.71
Why are severity ratings so useful?
- they provide a more precise estimate of how serious an illness is
p. 71
Why have some of the DSM-IV-TR diagnoses been combined in the DSM-5?
Give some examples….
- not enough evidence for differential etiology, course, or treatment response to justify separate labels
e. g., - ‘substance abuse’ and ‘dependence’ are replaced with ‘substance use disorder’
- ‘hypoactive sexual desire disorder’ and ‘female arousal disorder’ are replaced with ‘sexual interest/arousal disorder in women’
p.71
What are some crticisms of the DSM?
- The question of whether there are too many diagnoses
- Reliability of the DSM in everyday practise
- Validity of diagnostic categories
p.77-78
What is one side effect of having such a large number of diagnostic categories?
- Comorbidity (i.e., the presence of a second category)
p. 77
What percentage of people meet the criteria for a second diagnosis?
Why is this overlap likely to reflect?
- 45%
- this overlap may be a sign that we are dividing syndromes too finely
p.77
What is a subtle issue with the large number of possible diagnoses?
- Different diagnoses do not seem to be distinct in
- etiology or
- treatment
What is the dilemma when it comes to such a large number of categories?
- To lump them all together or to split into finer distinctions
What does the DSM specify must be present to meet criteria for a diagnosis?
- impairment or distress
DN is wondering if this applies to others as well as to self
- (e.g., a person with hoarding disorder may not be distressed by the hoarding but others are)
- can someone be classified as disordered when they are ignorant to the distress their behaviour is causing others and are not experiencing distress themselves
another thought - perhaps potential distress (masked by the behaviour) should be considered or
unconscious distress - a person with these behaviours would have to be experiencing distress at some level, but may not be conscious of it.
p.78
How does reliability of diagnoses compare in practise with that in research?
- reliability may not be as high in practise as it is in research studies
p. 79
What are some inherent problems in diagnosing people with mental illness?
- tendency to ignore a persons strengths when focussing on diagnosis
- labelling the person as schizophrenic rather than a person with schizophrenia
- while stigma can be increased with labels - it can also relieve stigma by aiding understanding of symptoms
p.80
How can we provide the best possible psychological assessment?
Use multiple techniques & multiple sources of information:
- Clinical Interviews
- Structures Interviews
- Assessment of Stress
- Semi-structured interview (LEDS)
- Self Report Stress Checklists (poorer reliability than LEDS)
- Personality Tests
- Self Report Personality Inventories (MMPI-II)
- Projective Personality Tests (Rorschach - TAT)
- Intelligence Tests
- Behavioural & Cognitive Assessment
- Direct Observation
- Self-Observation
- self monitoring or EMA (ecological momentary assessment)
- Cognitive Style Questionnaires (DAS dysfunctional attitude scale)
What are 4 Neurobiological Assessment Methods?
-
Brain Imaging
- CT (CAT) & MRI scans - brain structure
- PET - brain function & to a lesser extent structure
- fMRI - brain structure & function
-
Neurotransmitter Assessment
- postmortem analysis of neurotransmitters & receptors
- Assays of metabolites of neurotransmitters
- PET scans of receptors
-
Neuropsychological Assessment
- Behavioural tests (e.g., Halstead-Reitan & Luria-Nebraska - to assess motor speed, memory & spatial ability)
- deficits on particular tests help point to an area of brain dysfunction
- Behavioural tests (e.g., Halstead-Reitan & Luria-Nebraska - to assess motor speed, memory & spatial ability)
-
Psychophysiological Assessment
- Measures of electrical activity in the
- ANS (autonomic nervous system e.g., skin conductance)
- CNS (central nervous system e.g., EEG)
- Measures of electrical activity in the
p.94
What is a CT or CAT scan?
- Computerised axial tomography - assesses structural brain abnormalities
-
1. Moving beam passes into a horizontal cross section of the brain
- scanning 360 degrees
- a moving X-ray detector measures radioactivity that penetrates
- detecting subtle differences in tissue density
-
2. Computer used to construct two-dimensional image of cross-section
- detailed with optimal contrasts
-
3. Then machine scans another cross-section of brain
- resulting images can show
- enlargement of Ventricles (sign of degeneration
- location of tumours/blood clots
- resulting images can show
What device can be used to view the ‘living’ brain?
- MRI (Magnetic Resonance Imaging)
- superior to CT
- produces higher quality pictures
PROCESS
- large circular magnet causes hydrogen atoms in the body to move
- magnet force turned off, the atoms return to their original positions
- producing an electromagnetic signal
- signals read by computer & translated into pictures of brain tissue
ADVANCES
- has enabled location of delicate brain tumours previously deemed inoperable
p. 94
What is fMRI?
- functional Magnetic Resonance Imaging
- allows measurement of both brain structure & brain function
- measures blood flow in the brain (BOLD signal)
- it takes pictures so quickly that metabolic changes can be measured
- provides a picture of the brain at work
- rather than of its structure alone
p.95
What is the BOLD signal?
- in fMRI
- BOLD = blood oxygenation level dependent
- As neurons fire, blood flow increases to that area
- Thus blood flow in a particular region can reflect neural activity in that region
p.95
What is a PET scan?
- Positron Emission Tomography
- more expensive & invasive than MRI & fMRI
- measure both structure & function
- but brain structure is not as precise as in MRI & fMRI
PROCESS
- substance used by the brain is labelled with a short-lived radioactive isotope & injected into the bloodstream
- radioactive molecules of the substance emit a particle called a positron
- positron quickly collides with an electron
- a pair of high-energy particles shoot out from the skull in opposite directions
- detected by the scanner
- Computer analyses millions of such recordings & converts them into a picture of the functioning brain
- Images are in colour, fuzzy spots of lighter & warmer colours are areas where the substance has higher metabolic rates
Why is PET scan used a lot less than MRI & fMRI nowadays?
- because it is more invasive (injecting radioactively charged substance)
- more expensive
How can visual images of the ‘working’ brain be useful?
indicate sites of
- seizures
- brain tumours
- strokes
- trauma from head injury
- distrubution of psychoactive drugs in the brain
p.95
How are some current neuroimaging studies utilising these new technologies in studies of psychopathology?
- fMRI & PET being used to study abnormal brain processes linked to various disorders
- e.g., schizophrenia - failure of prefrontal cortex to become activated when performing cognitive tasks
- attempting to identify dysfunctional areas of the brain
- as well as deficits in communication between areas of the brain (called functional connectivity analysis)
p.95
What is a metabolite?
- commonly analysed in neurotransmitter assessment
- typically an acid produced when a neurotransmitter is deactivated
- high level of a particular metabolite indicates a high level of a neurotransmitter
- low level metabolite indicates low level of a neurotransmitter
What are two problems with using blood or urine metabolites to investigate brain function?
- these measures are not direct reflections of brain levels of neurotransmitters
- a more specific measure can be taken from metabolites in CSF drawn from spinal cord
- even still not a direct measure as levels here include the spinal cord
- these studies are correlational
- causality, directionality, third variable
- experimental evidence is needed
p.96
What is the difference between a neurologist & a neuropsychologist?
-
Neurologist - physician specialising in diseases or problems affecting the nervous system
- e.g., stroke, muscular dystrophy, cerebral palsy, or Alzheimer’s disease
- Neuropsychologist - psychologist who studies how dysfunction of the brain affects the way we think, feel, & behave
- work differently, but often collaboratively
- to learn how the NS functions & how to treat problems caused by disease or injury to the brain
What idea are neuropsychological tests based on?
- that different psychological functions (motor speed, memory, language)
- rely on different areas of the brain
- so by looking at these functions may provide clues about the area/location of damage to the brain
p.97
What are two neuropsychological tests?
- **Halstead-Reitan **
- Three of the H-R tests
- Tactile Performance Test - Time
- Tactile Performance Test - Memory
- Speech Sounds Perception Test
- valid for detecting behaviour changes linked to brain dysfunction
- from various conditions - stroke, tumours, head injury
- Three of the H-R tests
-
Luria-Nebraska
- based on work of Aleksandr Luria (1902 - 1977)
- 2.5 hours to complete - scoring is highly reliable
- Criterion validity established - correctly distinguish 86% patients & controls
- reveals potential damage to frontal, temporal, sensorimotor, or parietal-occipital area of either hemisphere
- 269 items divided into 11 sections designed to determine
- basic & complex motor skills
- rhythm & pitch anbilities
- tactile & kinaesthetic skills
- verbal & spatial skills
- receptive speech
- expressive speech ability
- writing
- reading
- arithmetic
- memory
- intellectual processes
p.97
What are two advantages of the Luria-Nebraska neurological test?
- it can control for educational level
- a version for 8-12 year olds helps pinpoint brain damage in children & evaluate educational strengths & weaknesses early in development
p.97
