Discuss issues associated with the classification and/or diagnosis of schizophrenia An important aspect of any classification system is its reliability, high inter-rater reliability is important as it means that each time the system is used it has the same outcome. There has been little consistency in the diagnosis of schizophrenia in the past due to vagueness of the classification systems and inconsistencies between them, it is difficult to achieve reliable diagnosis when there is no universally agreed definition of schizophrenia.In order to improve reliability of diagnosis a group of symptoms characteristic of schizophrenia but rarely found in other mental disorders were identified as first rank symptoms, these form the basis of the current DSM and ICD and have helped reduce misdiagnosis. However DSM and ICD systems do still differ in a few key ways, for example in the length of time symptoms have to be present for diagnosis, ICD is one month while DSM is six months, this is a significant difference given how quickly severe symptoms can present in acute onset schizophrenia.Another important issue in classification is the validity of the classification system, this is the degree to which the system measures what it set out to measure, in this case it refers to the appropriateness of the categories in diagnosing schizophrenia. Reliability can still be high if the classification system is consistently inaccurate, so high validity is important in ensuring patients get the correct diagnosis and subsequently the appropriate treatment.

Of particular importance is predictive validity, if someone is given a diagnosis of schizophrenia then it is predicted they will respond to certain treatments.It is possible for two patients to present entirely different symptoms and both receive a diagnosis of schizophrenia, this is likely to result in receiving the same treatment which may only be effective for some symptoms. As a result the concept of schizophrenia as a diagnosis has questionable validity. There are many subtypes of schizophrenia covering a vast array of symptoms so it can be difficult to distinguish between schizophrenia and similar disorders such as temporal lobe epilepsy which can lead to misdiagnosis.In addition co-morbidity is common in schizophrenics, they often show symptoms of depression and it is important that the patient receives a dual diagnosis so that appropriate treatment is given for both disorders.

There are also ethical issues with diagnosis of schizophrenia, there is a stigma of unpredictability and violence attached to the disorder. Labelling a person mentally ill may affect their ability to socialise, get a job or result in self-fulfilling prophecy whereby the patient begins to act mentally ill because they are being treated as though they are.It is possible in cases where symptoms are mild that diagnosis may actually exacerbate the condition by causing stress, family dispute and social drift due to the stigma attached to schizophrenia. Finally there seems to be cultural variation in diagnosis, African-Americans are diagnosed more frequently, although this may be due to genetic differences it is likely that cultural bias in the diagnostic criteria causes cultural differences in emotional expression to be misinterpreted as schizophrenic behaviour.