Classification Systems: Reliability

Inter-rater reliability

Reliability of a diagnosis refers to whether the same set of symptoms are diagnosed with the same disorder by two different clinicians

E.g. if two clinicians were presented with the symptom of auditory hallucinations, they should both diagnose the patient with schizophrenia

Intra-rater reliability (Test-Retest)

Diagnosis is reliable if it is consistent over two different time periods by the same clinician.

E.g. when a patient with anxiety has their symptoms retested 2 months later, they should still be diagnosed with anxiety.

Why may diagnosis be unreliable?

The same symptoms occur of several different disorders, therefore psychiatrists may diagnose a different disorder to the one present so the diagnosis can be unreliable.

e.g. depression may be diagnosed as PTSD as they both involve insomnia

Improvement of Reliability

Reliability of diagnoses has improved over years as newer improved version of the DSM and ICD have been published.

E.g. The symptoms of disorders have been made more specific and have links to time.

AO3: Reliable (1)

I: There is evidence to suggest that diagnosis using both the DSM IV and ICD 10 have impressive levels of agreement between clinicians

J: Brown (2001) tested the reliability of mood disorders and anxiety using the DSM IV and found it to be “excellent”. Galezzi et al (2004) found high inter-rater reliability for clinicians using the ICD-10 to conduct a joint interview

E: this demonstrates a usefulness of reliable diagnosis as encourages confidence in clinicians making consistent diagnoses

AO3: Unreliable (1)

I: there is evidence to suggest that diagnosis using the DSM V isn’t reliable for all disorders

J: Regier (2013) found that Major Depressive Disorder had a poor reliability score of 0.2 meaning only 20% of clinicians would agree on this diagnosis

E: this is problematic as it means for some disorders. Many patients may not be diagnosed or be misdiagnosed lead to incorrect treatment or failure to treat at all.

AO3: Reliable (2)

I: There is also evidence to suggest that using diagnostic tools such as the DSM give the same diagnosis when used over a long time period.

J: research evidence by brown et al (2011) demonstrates that the DSM-IV has excellent reliability schools for multiple mental health disorders. The test-retest reliability scores of specific phobias are 0.7 and for OCD it is 075.

E: this suggests that the DSM is a reliable diagnostic tool that can consistently identify mental health disorders in individuals over time

AO3: Unreliable (2)

I: However, assessment scores for some disorders show variation in diagnosis

J: in trials of the new DSM five Kupfer found that major depressive disorder and generalised anxiety both had low reliability scores.

E: this means the diagnosis of disorders could be different each time they visit a clinician, making them unreliable.