Reliability and validity in diagnosis and classification

• Explain what is meant by reliability in the diagnosis of schizophrenia. 


  Reliability of diagnosis refers to whether different psychiatrists agree when diagnosing an individual with schizophrenia.

  I.e. their diagnosis would be reliable if they both agree that the patient does or does not have schizophrenia.
• Explain what is meant by the reliability of the classification of

  schizophrenia.


  Reliability of classification refers to whether different classification systems (e.g. DSM-5 and ICD-10) agree when describing schizophrenia.

  I.e. their classifications would be reliable if they both describe schizophrenia in the same way.
• Explain what is meant by validity of the diagnosis of schizophrenia. 


  Validity of diagnosis refers to whether a psychiatrist can accurately identify whether a patient has schizophrenia or not.

  I.e. their diagnosis would be valid if they say they schizophrenia and they actually do.
• Explain what is meant by validity of the classification of

  schizophrenia.


  Validity of classification refers to whether the classification systems accurately describe schizophrenia.

  I.e. their classification would be valid if they accurately describe the symptoms experienced by those with schizophrenia.
• Identify the factors that can affect the reliability and validity of the diagnosis/ classification of schizophrenia.


  The use of different classification systems

  Co-morbidity

  Symptom overlap

  Culture bias

  Gender bias
• Explain what is meant by the use of different classification systems.


  Definition: The use of different classification systems refers to the use of the DSM-5 and the ICD-10.

  Example: E.g. The DSM-5 is used in America while the ICD-10 is typically used in the rest of the world.
• Explain why the use of different classification systems is an issue in the diagnosis/classification of schizophrenia. 


  Questions the reliability of the classification of schizophrenia i.e. whether there is agreement in how it is described.

  This is because the two classification system differ in terms of how they describe schizophrenia.

  Results in a confused understanding regarding what schizophrenia actually is and whether a patient has it or not.
• Define co-morbidity.


  Definition: Co-morbidity refers to when two or more conditions exist in the same individual at the same time.

  Example: E.g. individuals with schizophrenia are often diagnosed with another disorder alongside their schizophrenia such as depression.
• Explain why co-morbidity is an issue in the validity of diagnosis/classification of schizophrenia.


  This is because if an individual has schizophrenia, they may be incorrectly diagnosed with another disorder that shares similar symptoms such as bipolar disorder (affecting validity of diagnosis).

  This is an issue because unreliable and incorrect diagnoses would result in inappropriate support/treatment being provided e.g. wrong medication.
• Explain why co-morbidity is an issue in the reliability of the diagnosis/classification of schizophrenia. 


  It may also result in different psychiatrists diagnosing the same individual with different disorders e.g. one may diagnose them with schizophrenia while another diagnoses them with bipolar disorder (affecting reliability of diagnosis).

  This is an issue because unreliable and incorrect diagnoses would result in inappropriate support/treatment being provided e.g. wrong medication.
• Define culture bias. 


  Definition: Culture bias refers to the over or under-diagnosis of schizophrenia in people of different cultures.

  Example: E.g. In Britain, people of Afro-Caribbean descent are 7x more likely than white people to be diagnosed with schizophrenia.
• Explain why cultural bias is an issue in validity of the diagnosis/classification of schizophrenia. 


  Hearing voices is typically seen as a sign of a mental health condition such as schizophrenia. This could lead to people of Afro-Caribbean receiving an invalid (inaccurate) diagnosis of schizophrenia and could also result in an unreliable (inconsistent) diagnosis of schizophrenia as it depends what cultural background the psychiatrist is from.

  Can lead to labelling, stigmatisation and difficulties gaining employment
• Define symptom overlap.


  Definition: Symptom overlap refers to when different disorders share the same symptoms.

  Example: E.g. both schizophrenia and bipolar disorder involve symptoms such as delusions and avolition.
• Explain why symptom overlap is an issue in the diagnosis/classification of schizophrenia. 


  Questions the validity and reliability of the diagnosis of schizophrenia.

  May be incorrectly diagnosed with another disorder that shares similar symptoms such as bipolar disorder (affecting validity of diagnosis).

  May also result in different psychiatrists diagnosing the same individual with different disorders e.g. one may diagnose them with schizophrenia while another diagnoses them with bipolar disorder (affecting reliability of diagnosis).
• Define gender bias. 


  Definition: Gender bias refers to the over or under-diagnosis of schizophrenia in people of different genders.

  Example: E.g. women are typically under-diagnosed with schizophrenia.
• Explain why gender bias is an issue in the diagnosis/classification of schizophrenia.


  Questions the validity and reliability of the diagnosis of schizophrenia.

  Under-diagnosis of schizophrenia in women may not be due to them just being less likely to develop schizophrenia.

  Their cases may appear too mild for them to be diagnosed with schizophrenia. This could lead to women receiving an invalid diagnosis and could also receive an unreliable diagnosis as it may depend on the gender of the psychiatrist diagnosing them.

  Could lead women into not receiving the support/treatment they need.