Issues surrounding the classification and diagnosis of SZ Flashcards
What are the issues surrounding the classification and diagnosis of schizophrenia
Reliability and validity
Define reliability (of a diagnosis)
The level of agreement and consistency of the diagnosis by different psychiatrists across time and cultures.
Define inter-rater reliability
The level of agreement and consistency of the diagnosis by different psychiatrists
Define test-retest reliability
The level of agreement and consistency of a diagnosis over time given no change in symptoms
Define Validity (of a diagnosis)
The extent to which SZ is a unique syndrom with characteristics, symptoms, and signs. To be valid, patients with SZ should have different symptoms from patients with other disorders
What are the issues affecting validity
- co-morbidity
- gender bias
- culture bias
- symptom overlap
- range of symptoms
define co-morbidity
When 2 or more conditions occur together in the same individual at the same time
define culture bias
A tendecy to interpret all phenomena through the ‘lens’ of one’s own culture, ignoring the effects that cultural differences might have on behaviour
Define symptom overlap
Shared symptoms that could lead to an incorrect diagnosis. Often calls into question teh validity of classification.
Define range of symptoms
The are a range of symptoms that could be present for a diagnosis of SZ. e.g. positive and negative symptoms.
Give evidence for co-mobitity affecting validity
Buckley et al 2009:
found that 50% of patients with SZ have depression or substance abuse, 29% had PTSD and 23% had OCD.
Give evidence for gender bias affecting validity
Longnecker et al 2010:
found that since the 1980s men have been diagnosed more than women
Cotten et al 2009:
suggests this underdiagnosis is due to women having more closer relationship so get more support which leads to women with SZ functioning better than men with SZ.
Give evidence for culture bias affecting validity
Keith et al 1991:
found that 2.1% of African Americans are diagnosed with SZ compared to 1% of the white population. Many people from african cultures believe and praised for being able to communicate with ancestral spirits. This means they are more likely to report these experiences which are often misinterpreted as symptoms of SZ.
Give evidence of symptom overlap affecting validity
There is considerable overlap between symptoms of SZ and other disorders. e.g. bipolar disorder. This means that it is hard to define the boundries between SZ and other disorders.
give evidence of range of symptoms affecting validity
2 individual could display very different behaviour but still be diagnosed with SZ.
for example the DSM-5 requires one positive symptoms whereas the ICD-10 requires 2 negative symptoms.