Discuss Issues Relating to Reliability and Validity Surrounding the Classification and Diagnosis of Schizophrenia. (16 Marks)
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- Discuss Issues Relating to Reliability and Validity surrounding the Classification and Diagnosis of Schizophrenia (16 Marks)
- Reliability
- Definition - Consistency
- Inter-rater reliablity (the extent to which assessors agree on each other's assessments) is an important measure of reliability
- When it comes to diagnosis of schizophrenia or other mental health disorders this means the extent to which clinicians arrive at the same diagnosis for the same patients.
- Study: Cheniaux et al (2009) Got two psychiatrists to independently diagnose 100 patients using both ICD and DSM criteria.
- Findings: Inter-rater reliability was poor. One psychiatrist diagnosed 26 with schizophrenia according to the DSM and 44 according to the ICD. This pootr reliability is a weakness of diagnosis of schizophrenia.
- Study: Cheniaux et al (2009) Got two psychiatrists to independently diagnose 100 patients using both ICD and DSM criteria.
- When it comes to diagnosis of schizophrenia or other mental health disorders this means the extent to which clinicians arrive at the same diagnosis for the same patients.
- Inter-rater reliablity (the extent to which assessors agree on each other's assessments) is an important measure of reliability
- Definition - Consistency
- Validity
- Definition - Accuracy, the extent to which we are measuring what we want to measure.
- There are many validity issues to be acknowledged when diagnosing schizophrenia.
- Criterion Validity is a way of assessing the validity of a diagnosis. It determines whether different assessment systems arrive at the same diagnosis for the same patient.
- From Cheniaux et al's study it's clear that schizophrenia is more likely to be diagnosed using the ICD than the DSM.
- This suggests that schizophrenia is either over-diagnosed in the ICD or under-diagnosed in the DSM. EIther way this is poor validity and a weakness of the diagnosis of schizophrenia.
- From Cheniaux et al's study it's clear that schizophrenia is more likely to be diagnosed using the ICD than the DSM.
- Criterion Validity is a way of assessing the validity of a diagnosis. It determines whether different assessment systems arrive at the same diagnosis for the same patient.
- There are many validity issues to be acknowledged when diagnosing schizophrenia.
- Definition - Accuracy, the extent to which we are measuring what we want to measure.
- Co-Morbidity
- Definition- The phenomenon that two or more conditions occur together.
- If the two or more conditions occur together frequently this calls the diagnosis and classification of both conditions into question because what appears to be two conditions may be one.
- Supporting Study: Peter Buckley et al (2009) Found that around 1/2 of patients with a diagnosis of schizophrenia also have a diagnosis of depression (50%) or substance abuse (47%). Post-traumatic stress disorder also occurred in 29% of cases and OCD in 23%.
- This is an issue for both diagnosis and classification.
- In terms of diagnosis 1/2 of the patients have diagnosis of depression so therefore it could be down to human error - not being able to easily distinguish between the two conditions.
- In terms of classification it may be that severe depression looks like schizophrenia and vice versa. These may be seen as a single condition.
- This is a weakness of the diagnosis and classification of schizophrenia.
- This is an issue for both diagnosis and classification.
- Supporting Study: Peter Buckley et al (2009) Found that around 1/2 of patients with a diagnosis of schizophrenia also have a diagnosis of depression (50%) or substance abuse (47%). Post-traumatic stress disorder also occurred in 29% of cases and OCD in 23%.
- If the two or more conditions occur together frequently this calls the diagnosis and classification of both conditions into question because what appears to be two conditions may be one.
- Definition- The phenomenon that two or more conditions occur together.
- Symptom Overlap
- Definition: When two conditions have the same or similar symptoms
- Example: Both Schizophrenia and Bipolar Disorder involve positive symptoms such as delusions and negative symptoms like avolition.
- This affects both diagnosis and clasification.
- Under ICD criteria someone may be diagnosed as schizophrenic however, under the DSM they might be diagnosed with bipolar disorder.
- This is unsurprising given the overlap of symptoms . The DSM even suggets that bipolar disorder and schizophrenia might not be two seperate conditions.
- Under ICD criteria someone may be diagnosed as schizophrenic however, under the DSM they might be diagnosed with bipolar disorder.
- This affects both diagnosis and clasification.
- Example: Both Schizophrenia and Bipolar Disorder involve positive symptoms such as delusions and negative symptoms like avolition.
- Definition: When two conditions have the same or similar symptoms
- Reliability
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