Validity in diagnosing and Classification of schizophrenia

Question 1

What is validity?

Answer 1

• Accuracy of measuring what we intend to measure

- e.g if doctor gives an accurate diagnosis of schizophrenia

Question 2

What are the 2 types of validity?

Answer 2

• predictive

- descriptive

Question 3

What is predictive validity?

Answer 3

If valid:

• should lead to effective treatment
• should predict how disorders will develop

Question 4

What is descriptive validity?

Answer 4

• P’s diagnosed with schizophrenia should differ from p’s with other disorders

Question 5

What are the issues with validity?

Answer 5

• co morbidity
• culture
• gender bias
• symptom overlap

Question 6

How is co morbidity a weakness of validity?

Answer 6

• schizophrenia p’s often suffer substance abuse, depression or anxiety
• Buckley (2009): 50% of schizophrenia p’s have comorbid depression

Question 7

How does culture affect validity?

Answer 7

• African Americans more likely to be diagnosed with schizophrenia than white
• schizophrenia rates in Africa and west India are low
• due to cultural bias

Question 8

How does gender bias affect validity?

Answer 8

• males more likely to be diagnosed

Høye (2011)

• women express feelings more
• doctors more likely to say it’s life events or stress

Question 9

How does symptom overlap affect validity?

Answer 9

• schizophrenia symptoms are common in other disorders
• e.g schizophrenia/ bipolar = delusions and avolition
• there may be a disorder that includes bipolar and schizophrenia
• may not be separate disorders

Question 10

What arguments support that there is issues with validity?

Answer 10

• supporting research
• cultural differences
• self report measures

Question 11

What research supports issues with validity?

Answer 11

Swets (2014):

• meta analysis
• 12% of schizophrenia p’s met criteria for OCD
• 25% showed obsessive compulsive symptoms
• can’t conclude symptoms due to schizophrenia or OCD

Question 12

How does cultural differences support that there are issues with validity?

Answer 12

Casas (1995):

• many African Americans don’t want to share personal info with p’s of different races
• if diagnosed by doctor of different race, diagnosis is likely to be invalid

Question 13

How do self report measures support that there are issues with validity?

Answer 13

• p’s might need to do self report measures as part of diagnosis
• p’s don’t have insight into disorder
• not accurately report symptoms
• mistakenly recall wrong info
• invalid diagnosis

Question 14

What arguments suggest there isn’t low validity?

Answer 14

• DSM 5 addresses culture

- DSM 5 more objective

Question 15

How is the DSM 5 addressing culture go against there being issues with validity?

Answer 15

• now addresses cultural concepts of distress
• details how different cultures describe symptoms
• recognises how p’s in different cultures think and talk about psychological problems
• increase validity

Question 16

How does the DSM 5 being more objective increase validity?

Answer 16

• removes subtypes of schizophrenia
• the subtypes had poor predictive validity
• subtypes didn’t provide better targeted treatment or predictive treatment response
• DSM adapted to ensure high validity

Question 17

What is the conclusion for whether diagnosing and classifying schizophrenia is valid and reliable?

Answer 17

• validity is more difficult to access than reliability

- even if doctors agree there’s no guarantee diagnosis is right

Question 18

What research supports the conclusion of whether classifying and diagnosis schizophrenia is reliable and valid?

Answer 18

Rosenhan (1973):

• he and 7 p’s told psychiatric staff they had 1 symptom
• hearing voices saying ‘empty’, ‘hollow’ and ‘thud’
• all p’s were admitted to hospital w/ schizophrenia
• All doctors agreed with diagnosis - high reliability
• diagnosis was wrong - low validity