Reliability: classification systems

What is inter-rater reliability?

Whether the same set of symptoms would get the same diagnosis from different psychiatrists

What is test-retest reliability / intra-rater reliability?

A diagnosis can be considered reliable if the diagnosis is consistent over two different time periods for the same patient using the same psychiatrist (this can also be a result of the participant lying about / hiding symptoms, affecting reliability of diagnosis)

What makes a diagnosis reliable?

• Inter-rater reliability

• Test-retest reliability / intra-rater reliability

• Diagnosis may be unreliable as the same synoptics occur over several different disorders, potentially causing the psychiatrist to diagnose the wrong disorder

• Reliability of diagnosis has unproved over the years as improved versions of the DSM and ICD have been published

two strengths? (classification systems are reliable)

• Brown (2001) and Galeazzi et al (2004): evidence to suggest that diagnosis using both the DSM V and ICD 10 have impressive levels of agreement between clinicians

• Brown et al (2011): evidence to suggest using diagnostic tools such as DSM give the same diagnosis when used over a long time period (intra-rater reliability)

How are Brown (2001) and Galeazzi et al (2004) strengths?

Provide evidence to suggest that diagnosis using both the DSM V and ICD 10 have impressive levels of agreement between clinicians (inter-rater reliability). Brown (2001) tested the reliability of diagnoses of mood disorders and anxiety using the DSM IV and found it to be ‘excellent’. Galeazzi et al (2004) found high inter-rater reliability for clinicians using the ICD 10 to conduct a joint interview. This demonstrates the usefulness of reliable diagnosis as it encourages confidence in clinicians making a consistent diagnosis.

How is Brown et al (2011) a strength?

Provided evidence to suggest that using diagnostic tools such as the DSM gives the same diagnosis when used over a long period of time (intra-rater reliability). His evidence demonstrates that the DSM IV has excellent reliability scores did multiple mental health disorders. The test-retest reliability scores for specific phobias are at 0.7 and for OCD it is at 0.75. This suggests that the DSM is a reliable diagnostic tool that can consistently identify mental health disorders in individuals over time.

Two weaknesses? (classification systems are not valid)

• Regier (2013): evidence to suggest that diagnosis using the DSM V isn’t reliable for all disorders

• Kupfer: found reassessment scores fir some disorders show major variations in diagnosis (bad intra-rater reliability)

How is Regier (2013) a weakness?

Found evidence to suggest that diagnosis using the DSM V isn’t reliable for all disorders. His findings showed that major depressive disorder had a poor reliability score of 0.2, meaning that was only a 20% agreement between clinicians. This is problematic as it means some patients may be diagnosed leading to incorrect treatment, lowering reliability.

How is Kupfer a weakness?

Showed reassessment scores for some disorders show major variations in diagnosis, meaning they have poor intra-rater reliability. In trails of the new DSM 5, Kupfer found that major depressive disorder and generalised anxiety disorder both had low reliability scores, This means that fir sine diagnoses, this could be different each time the patient visits a clinician, making the diagnosis unreliable.