aqa  A2 Option: Reliability and validity in diagnosis and classification of schizophrenia, including reference to co-morbidity, culture and gender bias and symptom overlap.

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[space=10]If we cannot rely on the definition of Schizophrenia because it is unreliable and keeps changing then it invalidates the classification of the illness. This will then effect treatments, diagnosis and aetiology (finding the cause) as people will be taking part in studies/research and treatment programmes that may not even have the illness. Moreover there are ethical issues as they will be labelled incorrectly.

This means that research conducted in the early nineteen hundreds, when the definition bore little resemblance to what the illness translates to today (e.g. The Meta analysis by Zimbardo, which has collected data since the 1920) would be invalid. In fact, in May 2013 the DSM underwent a revision (in fact, the revision had been 14 years in the making), raising the symptom threshold for schizophrenia from 1, up to 2 main symptoms. This means that fewer people, theoretically, will gain a diagnosis of schizophrenia today than a few year ago. Does this mean that some people are not receiving treatment?  [space=10][toggle_box][toggle_item title=”DSM-5 and ICD-10: Duration of symptoms” active=”false”]Reliability in the diagnosis of schizophrenia is very important. This has been difficult to achieve in the past, particularly when psychiatrists in different countries have used different classification systems, For example in Europe, ICD-10 is used, whereas in the USA, DSM-5 is used. These classification systems have a different emphasis on the symptoms that are necessary for a diagnosis of schizophrenia. DSM requires symptoms to be present for at least six months for schizophrenia to be diagnosed, whereas ICD requires only one month. Because of this, it is possible that a person can be diagnosed with schizophrenia in one country but not in another, making the diagnosis of the disorder less reliable. This was demonstrated in a study by Copeland et al. (1971), who gave a description of a patient to US and UK psychiatrists. Sixty-nine percent of the US psychiatrists diagnosed schizophrenia, whereas only 2 percent of the UK psychiatrists diagnosed schizophrenia.

DSM-5 and ICD-10: No vs 7 subtypes

Even today, DSM-5 and ICD-10 have different criteria for the diagnosis and classification of Schizophrenia: ICD recognises 7 sub-types of schizophrenia, including ‘post-schizophrenic depression’ and ‘simple schizophrenia’ , with the DSM-V no longer distinguishing between its previous 5 sub-types. The DSM-V removed these due to validity issues. Patients’ predominant symptoms often change from one sub-type to another, sometimes overlapping multiple categories. This blurred distinctions between them and reduced the validity of a diagnosis. Not having this distinction between sub-types may lead to a more generic treatment for schizophrenia, not meeting the specific needs of the patient.[/toggle_item]

Type 1 vs Type 2 schizophrenia

Psychologists such as Crow believe that Schizophrenia is too broad a term because at least two very different conditions exist.Crow believes that individuals with positive symptoms and acute onset should be diagnosed as Type One Schizophrenic and those individuals with chronic onset with negative symptoms should be diagnosed as Type Two Schizophrenics.  Further evidence for this view comes from research that shows that Type 1 and Type 2 Schizophrenics do respond very differently to psychological and biological treatments, e.g. Typical and Atypical Phenothiazines have more success with relieving positive symptoms as does CBT.

Schizoid personality disorder

The diagnosis of schizophrenia is so specific that some people who show schizophrenic-like behaviour, but do not quite meet all the diagnostic criteria, are therefore not diagnosed as schizophrenic. These people are often given a diagnosis considered to be less serious, such as that of schizoid personality disorder. A criticism of the validity of schizophrenia could therefore be ‘How do we know we have set the right criteria?’ This question is not easy to answer because a psychiatric diagnosis relies on the psychiatrist’s experience rather than on physical test results.

Inter-rater reliability

The inter-rater reliability of two psychiatrists diagnosing Schizophrenia is exceptionally low, e.g. less then 50%. This is a very alarming statistic as it suggests that psychiatrists don’t know what they are doing. This is especially disturbing when you realise:

I.       That you can’t ever lose the label of being Schizophrenic (e.g. you can only be a Schizophrenic in remission).
II.      That once labelled, it has massive repercussions on how you are viewed and treated in society, stigmatisation.
III.      That incorrect diagnosis is probably the result of problems with defining Schizophrenia, e.g. if you can’t classify Schizophrenia how can you diagnose it?
IV.      Thus people who do not have Schizophrenia may be included in research which may result in invalid conclusions about the illness’ cause and/or treatment.

Validity of diagnoses

Rosenhan (1973): ‘Being Sane in Insane Places’ – Rosenhan (1973) and several collaborators (pseudo-patients) showed how easily schizophrenia can be misdiagnosed. They approached psychiatric hospitals saying they could hear voices saying ’empty’, ‘hollow’ and ‘thud’. This one symptom was enough for them to be admitted with a diagnosis of schizophrenia. Thereafter, Rosenhan and the pseudo-patients behaved normally, yet once the schizophrenia label was given, it stuck such that even normal behaviour was seen as schizophrenic; for example, waiting outside the dining room for a meal was said to be ‘characteristic of the oral-acquisitive nature’ or schizophrenia. Also, on their eventual release, most pseudo-patients were given the diagnosis of ‘schizophrenia in remission’.

This controversial study led psychiatrists (particularly in the USA) to refine the diagnostic process, to include longer-lasting symptoms. However, the use of deception was unethical. The diagnostic process was clearly flawed, but responsible psychiatrists would not expect healthy patients to invent psychiatric symptoms and risk hospital admission; nor would they turn someone away apparently in need.

In a second study Rosenhan threatened to send more pseudo patients but he did not. Embarrassingly staff at psychiatric hospitals all over the USA tried to detect non-existent “fake” patients and falsely identified large numbers of ordinary patients as impostors. The study concluded, “It is clear that we cannot distinguish the sane from the insane in psychiatric hospitals and that current methods are invalid and unreliable.” The study also illustrated the dangers of dehumanization and labelling in psychiatric institutions.

Co-morbidity

An issue involved in the diagnosis of schizophrenia is whether the condition actually does exist and whether it is distinct from other forms of mental disorder. A validity problem is that there is considerable overlap with conditions such as bipolar disorder. People with bipolar disorder also experience delusions and hallucinations; therefore diagnosing a person with schizophrenia may lead to a faulty diagnosis, because schizophrenia shares these important symptoms with bipolar disorder. A valid diagnosis, therefore, relies on a psychiatrist’s experience rather than simply the use of a classification system. One way around this problem is to diagnose on the basis of the severity of symptoms experienced by the individual, rather than just whether they are present.

Cultural differences

Afro-Caribbean’s who live in the UK, USA and other predominantly Caucasian societies are seven times more likely to be diagnosed as Schizophrenic then if living in a country that has predominantly black people. This again points to problems with validity and reliability of diagnosis as the statistic would be similar in both types of culture if classification and diagnosis were correct. One theory is that doctors may not understand black cultures and misdiagnose schizophrenia, e.g. some Caribbean cultures believe you should talk to relatives/friends after they have died. So, for instance, a grieving widow may tell a doctor she has been talking to her dead husband / or she may be observed talking to her dead husband. Either way, the idea is that many white UK doctors will not understand the norms of her culture and will diagnose schizophrenia or another mental illness.

Model Exam Answer

Explain issues associated with the classification and/or diagnosis of schizophrenia (10 marks)

“Reliability in the diagnosis of schizophrenia is very important. This has been difficult to achieve in the past, particularly when psychiatrists in different countries have used different classification systems, For example in Europe, ICD-10 is used, whereas in the USA, DSM-5 is used. These classification systems have a different emphasis on the symptoms that are necessary for a diagnosis of schizophrenia. DSM requires symptoms to be present for at least six months for schizophrenia to be diagnosed, whereas ICD requires only one month. Because of this, it is possible that a person can be diagnosed with schizophrenia in one country but not in another, making the diagnosis of the disorder less reliable. This was demonstrated in a study by Copeland et al. (1971), who gave a description of a patient to US and UK psychiatrists. Sixty-nine percent of the US psychiatrists diagnosed schizophrenia, whereas only 2 percent of the UK psychiatrists diagnosed schizophrenia.

A second issue involved in the diagnosis of schizophrenia is whether the condition actually does exist and whether it is distinct from other forms of mental disorder. A validity problem is that there is considerable overlap with conditions such as bipolar disorder. People with bipolar disorder also experience delusions and hallucinations; therefore diagnosing a person with schizophrenia may lead to a faulty diagnosis, because schizophrenia shares these important symptoms with bipolar disorder. A valid diagnosis, therefore, relies on a psychiatrist’s experience rather than simply the use of a classification system. One way around this problem is to diagnose on the basis of the severity of symptoms experienced by the individual, rather than just whether they are present.”

[There are two clear issues covered in this answer: reliability and validity. It is well focused throughout, and the ‘explanation’ of the two issues is sound and appropriate to the requirements of the question, showing good understanding of how these issues impact on the diagnosis of schizophrenia. There is a good deal of appropriate elaboration, which would push this answer into the top mark band, and it clearly demonstrates a Grade A standard answer.]