Reliability In Diagnosing And Classification Of Schizophrenia

Question 1

What is reliability?

Answer 1

• The consistency of a measurement

- e.g consistency of diagnosis of schizophrenia

Question 2

What are the 2 types of reliability?

Answer 2

• inter rated reliability

- test retest

Question 3

What is inter rater reliability?

Answer 3

If a different doctor gives the same diagnosis to the same p using the same classification system

Question 4

What is test retest?

Answer 4

If the same doctor gives the same diagnosis using the same classification system at a different time

Question 5

What are the issues with reliability?

Answer 5

• co morbidity
• culture
• gender bias
• symptom overlap

Question 6

How is co morbidity and issue with reliability?

Answer 6

• occurs as disorders share symptoms

- can be inconsistent in which disorder is diagnosed

Question 7

How is culture a weakness of reliability? (Copeland)

Answer 7

Copeland (1971)

• gave 134 US and 194 British psychiatrists descriptions of p’s
• 69% US diagnosed schizophrenia
• 2% British diagnosed schizophrenia

Question 8

How can gender bias affect reliability?

Answer 8

Loring and Powell (1988)

• psychiatrists asked to diagnose p’s (written cases)
• if male/ no info given: 56% diagnosed
• if female: 20% diagnosed
• no gender bias is psychiatrists was female

Question 9

How can symptoms overlap affect reliability?

Answer 9

• schizophrenia shares symptoms with other disorders
• e.g depression/ schizophrenia = avolition
• low inter rater reliability

Question 10

What are the strengths supporting that there is an issue with reliability?

Answer 10

• research support
• too many symptoms
• subjective

Question 11

What is the supporting research for there being an issue with reliability?

Answer 11

Cheniaux (2009)

• 2 psychiatrists diagnosed 100 p’s
• used DSM and ICD
• psychiatrists 1: diagnosed 26 (DSM) and 44 (ICD)
• psychiatrists 2: diagnosed 13 (DSM) and 24 (ICD)
• low inter rater reliability

Question 12

How does too many symptoms support that there are issues with reliability?

Answer 12

• p’s with same diagnosis can have different symptoms
• only need to have 2 out of 5 to be diagnosed
• must have delusions, hallucinations or disorganised speech
• 12 ways to meet criteria
• difficult to give reliable diagnosis

Question 13

How is diagnosing schizophrenia subjective?

Answer 13

• different doctors interpret same action in different ways
• doctor must decide if behaviour is classed as a symptom
• biases can lead to incorrect diagnosis
• low inter rater reliability

Question 14

What are the weaknesses of there being issues with reliability?

Answer 14

• DSM update

- methodology

Question 15

How is DSM updates a weakness of there being issues with reliability?

Answer 15

• newer versions have tightened criteria

- e.g clearly states list of symptoms for each disorders

Question 16

How is methodology a weakness that there are issues of reliability?

Answer 16

• in research psychiatrists don’t meet or speak to p
• real life interactions affect diagnosis
• low ecological validity
• reliability may be higher if diagnosing in real life

Question 17

what is comorbidity?

Answer 17

• p has 2 or more conditions

- e.g schizophrenia + depression, anxiety or bipolar

Question 18

how is culture a weakness of reliability? (Malgady)

Answer 18

Malgady (1987):

• Costa rice : hearing voices = spirits
• USA : hearing voices = schizophrenia

Question 19

what is the research to support that DSM updates are a weakness of there being issues with reliability?

Answer 19

Beck (1962):
- 54% concordance rate between doctors when diagnosing 153 p’s using DSM II

Soderberg (2005):
- concordance rate 81% using DSM IV