Reliability Of Classification Systems

Front 1

What does reliability of diagnosis mean?

Back 1

The consistency of a diagnosis, over time and between professionals. Refers to whether an individual would get the same diagnosis if they present the same symptoms to professionals at different times or to different professionals.

Front 2

What is inter-rater reliability and PPV?

Back 2

• Inter-rater reliability - extent to which two or more professionals give the same diagnosis to the patient.
  
• PPV: A PPV shows the reliability of a disorder's diagnosis, e.g. a PPV of 90 for schizophrenia shows 90% of those diagnosed would receive same diagnosis when re-assessed.
  

Front 3

What are some issues with reliability?

Back 3

Patient factors - unreliable accounts of symptoms.

Clinician factors - subjective interpretation of symptoms

Diagnostic system factors - lack of standardisation/objectivity in diagnosis.

Front 4

What did Goldstein find when investigating schizophrenia using the DSM-II and DSM-III?

Back 4

169 out of 199 agreement between DSM-II and DSM-III; high reliability across the systems over time.

0.8 agreement between Goldstein and two experts using DSM-III; high inter-rater reliability of schizophrenia diagnosis.

Front 5

What did Brown et al find when using the DSM-IV for anxiety and mood disorders?

Back 5

1. Good to excellent inter-rater reliability. There were disagreements on nature of symptoms, not the existence of them.
   
2. Some boundary diagnosis issues.
   
3. Shows good inter-rater reliability of the DSM-IV, however there were issues with reliability for boundary level patients.
   

Front 6

What did Jakobsen find when using the ICD-10 for schizophrenia and psychosis?

Back 6

87% PPV for schizophrenia diagnosis, showing the ICD-10 is a reliable tool for schizophrenia diagnois.

Front 7

What did Tarrahi et al 2014 find when using the DSM-IV and ICD-10 for drug addiction?

Back 7

Overall 0.95 inter rater reliability for both systems for diagnosing drug dependency and therefore both have high inter-rater reliability.

Front 8

What did Rosenhan find when using the DSM-II for schizophrenia?

Back 8

Despite presenting the same symptoms, 1 pseudopatient was diagnosed with manic depression with psychosis, whereas the others were diagnosed with schizophrenia. This shows the DSM-II can be argued as being unreliable for diagnosing schizophrenia in terms of inter-rater reliability.