Diagnosis of schizophrenia

Question 1

Diagnosis

Answer 1

• Classification systems - based on the idea that a group of symptoms can be classed together as a syndrome
• W/ underlying cause and separate from all other mental disorders.

Question 2

Classification systems

Answer 2

1. DSM-15 - USA

2. ICD-10 - WHO

Question 3

What is schizophrenia seen as?

Answer 3

• Separate mental disorder with a distinct set of symptoms = diagnosed in a reliable and valid way

Question 4

Diagnosis-reliability

Answer 4

• Reliability concerns the consistency of symptom measurement and affects diagnosis in 2 ways

1. Test-retest reliability
2. Inter-rater reliability

Question 5

Test-retest reliability

Answer 5

• Clinician makes the same diagnosis on separate occasions from the same info

Question 6

Inter-rater reliability

Answer 6

• Different clinicians make identical, independent diagnosis of the same patient

Question 7

Beck et al (1962)

Answer 7

• 54% concordance rate between experienced practitioners’ diagnosis when assessing 153 patients

Question 8

Soderberg et al (2005)

Answer 8

• Concordance rate of 81% using the DSM classification system
  = Classification systems - more reliable over time

Question 9

Nilsson et al (2000)

Answer 9

• 60% concordance rate between practitioners using ICD

= DSM more reliable

Question 10

Read et al (2004)

Answer 10

• Test-retest reliability of schizophrenia diagnosis = 37% concordance rate
• 1970 study - 194 British and 134 US psychiatrists provided a diagnosis;
  69% USA
  2% British

= diagnosis never been fully reliable

Question 11

Seto (2004)

Answer 11

• ‘Schizophrenia’ re-labelled ‘integration disorder’ in Japan
  = Difficulty of attaining a reliable diagnosis

= Schizophrenia as a separate disorder = doesn’t exist.

Question 12

Jakobsen et al (2005)

Answer 12

• Tested reliability of ICD-10
• 100 Danish patients with a history of psychosis
• Assessed using operational criteria
  = Concordance rate of 98%
  = High reliability of clinical diagnosis of schizophrenia - up to date classification

Question 13

Evaluation - Strength

Answer 13

• DSM classification system = more reliable than ICD - symptoms outline for each category = specific
• Diagnosis assessed at 81% superior to anxiety 63%
• Reliability superior to validity