Classification and Diagnosis

Question 1

What is diagnosis?

Answer 1

• classification by symptoms
• important in treatment and clinical care
• correct diagnosis can provide base rates, causes and treatments
  Currently:
• ICD-10 (WHO)
• DSM-5 (APA)

Question 2

Describe early classification systems

Answer 2

Kraepelin (1883)
- psychopathology classified into different pathologies, different causes and symptoms
- 2 groups of syndromes:
Dementia Praecox (chemical imbalance) - SZ similar
Manic-depressive psychosis (irregular metabolism)

Question 3

What is reliability?

Answer 3

Reliability = consistency of measurement:

• inter-rater = agreement between observers
• test-retest = extent to which people being observed twice/ same test twice have a similar result
• alternate-form reliability = avoids practise effects - giving two tests and seeing if it consistent
• internal consistency = assesses whether items on a test are related to each other (correlate with)

Question 4

What is validity?

Answer 4

Validity = whether measures measure what it is meant to

• unreliable measures = not have good validity
• yet reliability does not guarantee validity
• content validity = whether a measure adequately samples the domain of interest
• construct validity = interpretation of a test = can we make accurate predictions based on the result (we don’t have lab tests so this provides measure for accurate predictions, information of treatment etc)

Question 5

What is the ICD classification system?

Answer 5

• developed by World Health Organisation
• 1939: mental disorders added to lists of causes of death
• 1948: list expanded to include disease, injury and death (added psychological disorders but not well accepted)
• 1969: mental disorders are more accepted and more info on diagnoses (practise to diagnose varied)

ICD - 10 developed in 1992
ICD-11 due for release in 2022 (re-organisation, new sections)

Question 6

What is the DSM-5 classification system?

Answer 6

Developed by APA
APA (1952) - First (DSM)
1968: DSM-II
1980: DSM-III (had the most substantial change from DSM-II)
2000: DSM-IV-TR
2013: DSM-5

More recent = more categories and more disorders
DSM-1 = 106 diagnoses
DSM-5 = 300 +

DSM-5
- section 1: basics
- section 2: 22 chapters, diagnostic criterai and coding
- section 3: emerging measure and models (alternative and conditions requring further study)
check notion for axis

Question 7

Highlight some differences between DSM 4 and 5

Answer 7

DSM-4 = axis classification and wider appreciation for individual circumstances
DSM-5 - non-axial and organised according to relationships between the disorder groups
- evolves with science

DSM-4 = mood disorders include SZ and biploar
DSM- 5 = separate chapters
DSM-4 = anxiety chapter
DSM-5 = does not include OCD (new chapter)

Question 8

Describe section 3 of DSM-5 briefly

Answer 8

• providing more dimensional approach to assessment measurements (loads of measures/scale of symptom severity and disability assessment)
• cultural formulation: includes an interview and identifying influences of culture on presentations of care - avoids stereotyping (used at the beginning or throughout)
• Conditions for further study (insufficient evidence for section 2 and shouldn’t be used for diagnostic purpose)
• Alternative models - allows continuity with current practice but also introduce a new approach in addressing shortcomings

check notion for info of these !

Question 9

Provide some criticism of DSM

Answer 9

• DSM makes it easier for minor symptoms to receive a diagnoses (due to more diagnosis, decreased number of symptoms and decreasing symptoms required for diagnoses)
• too many minute distinctions based on small differences in symptoms (cormorbidity)- those who meet one diagnoses = 45% meet for another criteria
• many disorders share the same risk factors
• different disorders are not distinct in etiology or treatment
• categorical classifications (dimensional allows us to understand the degree of the presence) - although categorical defines a threshold for treatment/guidance = may be arbitrary
• increased explicitness of dsm = improved reliability but some room for disagreement / subjective (e.g. ‘abnormally elevated mood’ - what is abnormal?)
• diagnosing may encourage stereotyping or stigmatisation
• diagnostic catergory applied - may lose sight of the uniqueness ofthe person (refer to people as schizophrenic)

Question 10

What is the difference between a categorical and a dimensional diagnostic strategy?

Answer 10

categorical = you either have it or you don't
dimensional = the degree to which it may be present

Question 11

Describe the reliability of the DSM in everyday practise

Answer 11

before DSM III - poor inter-rater

- growing in reliability but much room for disagreement due to subjective definitions (e.g. abnormally elevated)