Explain Issues of Reliability and Validity Associated with the Classification and Diagnosis of Schizophrenia

875 Words4 Pages
The reliability of the diagnosis of schizophrenia is bases on the extent to which different psychiatrists can agree on the same diagnosis of a patient and the validity is based on the extent to which psychiatrists can agree on what (the diagnosis of) schizophrenia actually is. The existence of classification systems such as the DSM or ICD claim to lead to a greater agreement on the diagnosis of schizophrenia. The different classification systems are each used in different cultures: ICD in the UK and DSM in the US. However the use of different systems of classification has problems because even though (theoretically) they both show diagnosis of SZ, they both describe schizophrenia in different ways. This is shown in a follow up study of Whaley’s inter rater reliability correlation of +.11, by Copeland et al. Copeland carried out a study by giving descriptions of a patient to US and UK psychiatrists, he found that 69% of the US psychiatrists diagnosed SZ compared to the 2% of UK psychiatrists, proving there are issues with the reliability of diagnosis as there is such a larger % difference. Although we can argue that this study can’t be generalised to prove issues of reliability as the study only used one patient and only two countries but it does support the fact that different cultures see SZ differently. A more famous study that shows the unreliability of diagnosis is the study by Rosenham. Rosenham demonstrated the unreliability of diagnosis by sending a group of ‘pseudopatients’ to a psychiatric hospital claiming to be ‘hearing voices’. All of the ‘patients’ were admitted with the diagnosis of SZ. During their stay at the hospital the ‘patients’ showed no further signs of abnormality and yet they were not discharged due to the fact the staff didn’t realise they were normal. This study lead to suggestions that situational factors and expectations may be
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