Issues in the diagnosis of schizophrenia (OCR A-Level Psychology): Revision Notes
12.1.2 Issues in the diagnosis of schizophrenia
Reliability and validity in diagnosis and classification of schizophrenia:
Diagnosed using:
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DSM – if a patient shows at least 2 symptoms for at least 6 months
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ICD Reliable diagnosis: The extent diagnoses are consistent
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Inter-reliability: When multiple doctors agree on the same diagnosis for a patient with certain symptoms e.g. hallucinations or delusions
Evaluation:
(1)
P: Different manuals are used to diagnose schizophrenia in different countries
E: For example, the DSM is commonly used in America, whereas the ICD is more commonly used in European countries.
E: As there are differences between the criteria in each manual, the diagnosis will be different depending on the country the patient is being assessed, therefore making the diagnosis unreliable.
(2)
P: Diagnosis can change over time as the criteria for the DSM and ICD are constantly updated
E: This could mean that people may no longer meet the criteria for diagnosis of schizophrenia, even though their symptoms haven't changed.
E: Therefore, someone diagnosed with schizophrenia in the past, may no longer receive the same diagnosis, resulting in low reliability
Valid diagnosis:
When the classification of schizophrenia is a true reflexion of the disorder the patient suffers from
- An invalid diagnosis is a problem as it suggests there is a lack of agreement over what schizophrenia is.
Evaluation:
(1)
P: There can be gender bias present when diagnosing schizophrenia
E: For instance, men are far more likely to be diagnosed with schizophrenia than women. This may be because women are seen as better able to cope with their symptoms
E: Therefore, this suggests that the classification of schizophrenia lacks validity
(2)
P: There are issues with co-morbidity affecting the validity of research
E: For instance, Buckley found that 50% of schizophrenia patients also had a diagnosis of depression
E: This supports the idea that there are problems with validity as it could mean that the two disorders the patient is diagnosed with are one disorder
This issue is also made problematic by:
Co-morbidity: One individual having more than one mental disorder e.g schizophrenia and depression
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This could mean that the two disorders a patient is diagnosed with are one disorder. Symptom overlap: When two or more disorders share the same symptoms needed for classification e.g. schizophrenia and bipolar share symptoms such as delusions and avolition
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This could mean that the same patient could receive two different diagnosis
Evaluation:
P: Diagnostic criteria are updated over time, affecting reliability.
E: Updates to the DSM and ICD mean that individuals previously diagnosed with schizophrenia may no longer meet the new criteria despite no change in symptoms.
E: This temporal inconsistency leads to low reliability in diagnosis.
P: Gender bias affects the validity of schizophrenia diagnoses.
E: Men are more frequently diagnosed with schizophrenia than women, possibly because women are seen as better able to cope with symptoms.
E: This suggests that the classification system may not validly reflect the true prevalence of schizophrenia across genders.
P: Co-morbidity challenges the validity of schizophrenia diagnoses.
E: Research by Buckley found that 50% of schizophrenia patients also had a diagnosis of depression.
E: This high rate of co-morbidity suggests that what is diagnosed as two separate disorders might be manifestations of a single disorder, questioning the validity of the diagnosis.
P: Symptom overlap further complicates the validity of schizophrenia diagnoses.
E: Schizophrenia and bipolar disorder share symptoms such as delusions and avolition.
E: This symptom overlap can lead to patients receiving different diagnoses depending on the clinician, undermining the validity of the classification system.