Outline and evaluate issues surrounding the Classification and diagnosis of Schizophrenia with
reference to reliability and validity (16 marks)
There have been many issues surrounding the diagnosis and classification of Schizophrenia,
especially with regard to validity and reliability.
Classification Issues with reference to validity and reliability
Many researchers e.g. Rosenhan believe that Schizophrenia is an impossible illness to classify.
Since 1911, when the illness was first described as Dementia Praecox, there has been great
controversy concerning what symptoms should be used to define the illness.
The DSM IV recognises 5 subtypes of schizophrenia (although this has now recently
changed).The last few years have been particularly important in the evolving definition of
Schizophrenia as the criteria for the illness has changed considerably. For example:
psychologists believe that Schizophrenia is too broad a term because at least two very different
conditions exist.
It is believed 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 drugs have more success with
relieving positive symptoms as does CBT.
Moreover, Schizophrenia has many different categories and symptoms, e.g. Paranoid, Catatonic,
Disorganised etc. Some of these subtypes have very different qualities; especially Catatonic
Schizophrenia where the person can lay motionless in rigid poses for days.
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.
Issues surrounding diagnosis of Schizophrenia including reliability and validity
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.
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reference to reliability and validity (16 marks)
There have been many issues surrounding the diagnosis and classification of Schizophrenia,
especially with regard to validity and reliability.
Classification Issues with reference to validity and reliability
Many researchers e.g. Rosenhan believe that Schizophrenia is an impossible illness to classify.
Since 1911, when the illness was first described as Dementia Praecox, there has been great
controversy concerning what symptoms should be used to define the illness.
The DSM IV recognises 5 subtypes of schizophrenia (although this has now recently
changed).The last few years have been particularly important in the evolving definition of
Schizophrenia as the criteria for the illness has changed considerably. For example:
psychologists believe that Schizophrenia is too broad a term because at least two very different
conditions exist.
It is believed 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 drugs have more success with
relieving positive symptoms as does CBT.
Moreover, Schizophrenia has many different categories and symptoms, e.g. Paranoid, Catatonic,
Disorganised etc. Some of these subtypes have very different qualities; especially Catatonic
Schizophrenia where the person can lay motionless in rigid poses for days.
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.
Issues surrounding diagnosis of Schizophrenia including reliability and validity
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.
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