Validity + Reliability - OCD

Question 1

What is a valid diagnosis?

Answer 1

Should be representative of what the patient is suffering from + lead to an effective treatment

Question 2

How can normal behaviour be mistaken for OCD?

Answer 2

75% of adults have unwanted thoughts and mild checking behaviour = danger of over-medicalising normal behaviour

Question 3

When is behaviour classed as OCD

Answer 3

When it interferes with everyday time

Question 4

How could the diagnosis of OCD be wrong?

Answer 4

There may be different subsystems and OCD is just an umbrella term. BUT many people with OCD do share the same symptoms.

Question 5

What is Comorbid? (Use if just on validity)

Answer 5

1 or more type of disorder at the same time = common with OCD
e.g. being on the Autistic spectrum which may show some symptoms of OCD

Question 6

What did Stein do?

Answer 6

Trainee lay interviewers interviewed someone for OCD oner the phone:

• Came up with a sample they believed had OCD
• Ps then blindly reinterviewed by specialists

Question 7

What did Stein find?

Answer 7

• Trainee prevalence for OCD = 3.1%

- Specialists = 0.6%

Question 8

What does Stein’s study show?

Answer 8

Some may be overestimating the degree of interference/distress on the individual = GPs do not always diagnose validly

Question 9

What have studies on comorbidity found? (Use if just on validity)

Answer 9

67% of those with OCD also have depression

Question 10

What did Goodman do? (Use if just on validity)

Answer 10

Tested the validity of the Yale-Brown scale

Question 11

What did Goodman find? (Use if just on validity)

Answer 11

• YBs correlated with 2-3 independent measures for OCD
• Patients showed YBs was sensitive to drug induced changes = score went down
• Reductions in YB score reflected improvement

Question 12

What does Goodman’s study show? (Use if just on validity)

Answer 12

YBs is a valid instrument for assessing OCD, BUT depends on how much we trust the original scales

Question 13

What did Rasmussen an Eisen find?

Answer 13

Certain factors are common in all OCD cases:

- Anxiety, fear of something terrible happening and belief that compulsions provide relief

Question 14

What is reliability of diagnosis?

Answer 14

The extent to which a patient will receive the same diagnosis from different doctors and at different times

Question 15

How can symptoms of OCD be found in other disorders?

Answer 15

E.g. some symptoms of eating disorders can appear OCD like = a GP might diagnose as OCD but a specialists may diagnose as something different

Question 16

How is there ambiguity in the diagnosis system?

Answer 16

E.g. what is distress and how much distress is enough to diagnose as OCD

Question 17

What is Diagnosis bias? (Use if just on reliability)

Answer 17

Some stereotyping of who has OCD e.g older women and housewives.
May stop some people going to get looked at (e.g. men)

Question 18

What did Goodman et al do?

Answer 18

Study involving 4 raters and 40 patients looking at the inter-rater reliability of YB scale

Question 19

What did Goodman et al find?

Answer 19

The inter-rater reliability for YB score + each of the 10 individual items was excellent

Question 20

What does Goodman et al’s study show?

Answer 20

YB scale is a reliable instrument for measuring the severity of illness in patients

Question 21

What did Lennkh do? (Use if just reliability)

Answer 21

Studied 66 female patients who met the DSM-IV criteria for anorexia

Question 22

What did Lennkh find? (Use if just reliability)

Answer 22

12 patients met the DSM-III-R criteria from lifetime OCD: 7 patients had current OCD and 5 had a past history of OCD
- Patients with comorbid OCD showed a significantly higher life time prevalence of bipolar etc

Question 23

What does Lennkh’s study show?

Answer 23

Shows that OCD is often comorbid with eating disorders

- shows how different individuals may diagnose

Question 24

What did Brown et al do?

Answer 24

Carried out 2 interviews, 2 weeks apart on 1400 patients

- Investigated various anxiety disorders and depression

Question 25

What did Brown et al find?

Answer 25

The inter-rater reliability for OCD was excellent and higher than other anxiety disorders or depression

Question 26

What does Brown et al’s study show?

Answer 26

Suggests that the presence of compulsions makes OCD easier to diagnose