Diagnosis and classification Flashcards
classification and diagnosis
-Schizophrenia has no one defining characteristic. It is a cluster of seemingly unrelated symptoms.
ICD-10
• Used by the WHO
• Two or more negative symptoms are needed.
DSM-V
• Manual used by the APA
• 1 positive symptom is sufficient for diagnosis.
positive symptoms
Positive Symptoms - the addition of an experience
• Hallucinations
• Unusual sensory experience
• Generally visual or auditory, but not exclusively.
• Delusions
• Irrational beliefs
• Grandeur (Believe important historical figure), paranoid (someone get you),external control.
• Disorganised Speech
• Incoherent, or speaker changes topics mid sentence.
negative symptoms
-The loss of an experience
• Avolition
• Sometimes called Apathy
• Struggle with goal directed behaviour
• Motivation.
• Andreason (1982) - three signs of avolition
• Poor hygiene, lack of persistence in work or education and lack of energy.
• Speech Poverty
• Reduction in the amount and quality of speech.
Reliability and validity of diagnosis
A good diagnostic tool needs to be reliable and valid.
• Reliability = Consistency / repeatable
• Validity = Legitimacy-measures what is claiming to measure
There are several things that can get in the way of validity.
• Co-morbidity
• Symptom overlap
• Gender Bias
• Culture Bias
Limitation-issue of reliability
One problem with the diagnosis and classification of schizophrenia is the lack of reliability.
Reliability refers to consistency. An important measure of consistency of diagnosis is inter-rater reliability - the extent to which independent assessors come to the same conclusions regarding a diagnosis.
Cheniaux et al. (2009) Had two psychiatrists independently diagnose 100 patients using both
DSM and ICD criteria. It was found that inter-rater reliability was poor, with one psychiatrist diagnosing 26 patients with schizophrenia according to the DSM and 44 according to the ICD, whereas the other diagnosed 13 with the DSM and 24 with the ICD.
This inconsistency is a serious limitation in the classification and diagnosis of schizophrenia.
Limitation-issue of comorbidity
Comorbidity refers to the fact that two or more conditions occur together. If conditions occur together a lot of the time then this calls into question the validity of the diagnosis and classification because they might actually be a single condition.
Schizophrenia is commonly diagnosed with other conditions.
In one review Buckley at et (2009) concluded that around half of patients with schizophrenia also have a diagnosis of depression (50%) or substance abuse (47%).
This is a problem for classification because it means schizophrenia may not exist as a distinct condition, and is a problem for diagnosis as it suggests that at least some people diagnosed with schizophrenia may instead have unusual cases of conditions like depression.
Limitation-symptom overlap
Another limitation of schizophrenia diagnosis is the existence of symptom overlap with other conditions.
There is considerable overlap between the symptoms of schizophrenia and the symptoms of other conditions, for example both schizophrenia and bipolar disorder involve positive symptoms such as delusions, and negative symptoms such as avolition.
In terms of classification this suggests that schizophrenia and bipolar may not be two different conditions but variations of a single condition. In terms of diagnosis it means that schizophrenia is hard to distinguish from bi-polar disorder.
As with comorbidity, symptom overlap means that schizophrenia may not exist as a distinct condition and that even if it does it is hard to diagnose. So both its classification and diagnosis are flawed.
limitation-issue of gender bias
A further limitation of schizophrenia diagnosis is the existence of gender bias. Since the 1980s men have been diagnosed with schizophrenia more commonly than women.
Cotton et al. (2009) suggest this is due to the fact that women have closer social and familial relationships than men and hence get more support.
This leads to women with schizophrenia functioning better than men, which may explain why some women have not been diagnosed with schizophrenia where men with similar symptoms might have been; the better interpersonal functioning may bias practitioners to underdiagnose schizophrenia, either because symptoms are masked altogether or because of the quality of interpersonal functioning makes the case seem too mild to warrant a diagnosis.
This suggests that the validity of the diagnosis of schizophrenia is poor because our procedures for diagnosis work well only on patients of one gender.
Limitation-issue of culture bias
The further limitation of schizophrenia diagnosis is the existence of culture bias.
Afro-Caribbean people living in the UK are up to 10 times as likely to receive a diagnosis as white British people, although people living in Afro-Caribbean countries are not, ruling out a genetic vulnerability. The most likely explanation for this is culture bias in diagnosis of clients by psychiatrist from a different cultural background.
Some symptoms of schizophrenia, particularly hearing voices, have different meanings in different cultures. For example in some Afro-Caribbean societies voices may be attributed to communication from ancestors. However, when presented to a practitioner from a different culture, these experience may seem bizarre or irrational.
This appears to lead to an over interpretation of symptoms in black British people (Escobar 2012). This means the Afro-Caribbean people may be discriminated against by a culturally biased diagnostic system.
