Reliability and validity in the 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.

  What it questions: This questions the reliability of the classification of schizophrenia i.e. whether there is agreement in how it is described.
• Explain why the use of different classification systems causes issues.

  Why: This is because the two classification system differ in terms of how they describe schizophrenia. The DSM-5 requires a positive symptom to be present however the ICD-10 does not (negative symptoms are sufficient).

  Why it is an issue: This is an issue because it 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.

  What it questions: This questions the validity of the classification of schizophrenia i.e. whether it been accurately described.
• Explain why co-morbidity is an issue?

  Why: This is because if schizophrenia often presents alongside another condition, it would question whether they have been inaccurately described as two different disorders when in fact they may be better described as one.

  Why it is an issue: This is an issue because it means we may not have a great understanding the various symptoms that can be involved in schizophrenia and, in turn, what is the most appropriate and effective treatment to provide.
• 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.

  What it questions: This questions the validity and reliability of the diagnosis of schizophrenia.
• Explain why symptom overlap is an issue.

  Why: This is because if an individual has schizophrenia, they may be incorrectly diagnosed with another disorder that shares similar symptoms such as bipolar disorder. It may also result in different psychiatrists diagnosing the same individual with different disorders.

  Why it is an issue: 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.

  What it questions: This questions the validity and reliability of the diagnosis of schizophrenia.
• Explain why culture bias is an issue.

  Why: 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.

  Why it is an issue: This is an issue because a diagnosis of schizophrenia can lead to labelling, stigmatisation and difficulties gaining employment. A wrong/inconsistent diagnosis can also lead to problems of receiving inappropriate treatment.
• 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.

  What it questions: This questions the validity and reliability of the diagnosis of schizophrenia.
• Explain why culture bias is an issue.

  Why: This is because the under-diagnosis of schizophrenia in women may not be due to them just being less likely to develop schizophrenia. Instead it may be due to the fact that women typically experience less negative symptoms than men so are able to function better.

  Why it is an issue: This is an issue because it could lead women into not receiving the support/treatment they need.