Validity + Reliability - OCD Flashcards
What is a valid diagnosis?
Should be representative of what the patient is suffering from + lead to an effective treatment
How can normal behaviour be mistaken for OCD?
75% of adults have unwanted thoughts and mild checking behaviour = danger of over-medicalising normal behaviour
When is behaviour classed as OCD
When it interferes with everyday time
How could the diagnosis of OCD be wrong?
There may be different subsystems and OCD is just an umbrella term. BUT many people with OCD do share the same symptoms.
What is Comorbid? (Use if just on validity)
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
What did Stein do?
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
What did Stein find?
- Trainee prevalence for OCD = 3.1%
- Specialists = 0.6%
What does Stein’s study show?
Some may be overestimating the degree of interference/distress on the individual = GPs do not always diagnose validly
What have studies on comorbidity found? (Use if just on validity)
67% of those with OCD also have depression
What did Goodman do? (Use if just on validity)
Tested the validity of the Yale-Brown scale
What did Goodman find? (Use if just on validity)
- 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
What does Goodman’s study show? (Use if just on validity)
YBs is a valid instrument for assessing OCD, BUT depends on how much we trust the original scales
What did Rasmussen an Eisen find?
Certain factors are common in all OCD cases:
- Anxiety, fear of something terrible happening and belief that compulsions provide relief
What is reliability of diagnosis?
The extent to which a patient will receive the same diagnosis from different doctors and at different times
How can symptoms of OCD be found in other disorders?
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
How is there ambiguity in the diagnosis system?
E.g. what is distress and how much distress is enough to diagnose as OCD
What is Diagnosis bias? (Use if just on reliability)
Some stereotyping of who has OCD e.g older women and housewives.
May stop some people going to get looked at (e.g. men)
What did Goodman et al do?
Study involving 4 raters and 40 patients looking at the inter-rater reliability of YB scale
What did Goodman et al find?
The inter-rater reliability for YB score + each of the 10 individual items was excellent
What does Goodman et al’s study show?
YB scale is a reliable instrument for measuring the severity of illness in patients
What did Lennkh do? (Use if just reliability)
Studied 66 female patients who met the DSM-IV criteria for anorexia
What did Lennkh find? (Use if just reliability)
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
What does Lennkh’s study show?
Shows that OCD is often comorbid with eating disorders
- shows how different individuals may diagnose
What did Brown et al do?
Carried out 2 interviews, 2 weeks apart on 1400 patients
- Investigated various anxiety disorders and depression
What did Brown et al find?
The inter-rater reliability for OCD was excellent and higher than other anxiety disorders or depression
What does Brown et al’s study show?
Suggests that the presence of compulsions makes OCD easier to diagnose
