Classification and diagnosis of schizophrenia:
Schizophrenia means split mind - where there is a loss of contact with reality. Sufferers usually find it hard to distinguish between reality and fantasy.
There are two types of symptoms, positive and negative
Positive symptoms are excess distortion of a normal function
Negative symptoms are a loss of normal function
The 2 major classification systems for psychological disorders are DSM - IV and ICD - 10.
DSM - IV - American psychiatric associations
ICD - 10 - World health organisation
Reliability of diagnosis:
Reliability is the extent to which differnet psychiatrists cana gree on the same diagnosis when assessing patients
There are diffent classificatiopn systems
- the issue with this is that both the ICD - 10 and the DSM - IV describe schizophrenia in different ways, which creates problems in assessing reliability.
WHALLEY found that inter - rater reliability (how similar are peopl's diagnosis) correlations for the diagnosis of schizophrenia was as low as 0.11.
ROSENHAM demonstarated the unreliability of diagnosis by arranging for pseudopatients to present themselves to psychiatric hospitals claiming to be hearing voices. All were diagnosed with schizophrenia and admitted despite the fact they displayed no further symptoms during their hospitalisation. Throughout their stay none of the staff recognised that tehy actually didn't suffer from schizophrenia.
Everyone taht displays symptoms gets the diagnosis of schizophrenia and not another disorder. Furtehrmore there is little consistency in diagnosis over the 3o years: USA 20% diagnosed in the 1930s and 80% diagnosed in the 1950's however, in the UK it was 20% for 1930s - 1950s
Solution to solve the problem of reliability
"First rank symptoms": identify a group of symptoms charcteristic of schizophrenia but rarely found in other mental illnesses, these are:
- Delusions of being controlled by others
- Broadcast of thoughts
- Hearing voices that comment on thoughts/ actions
Another solution would be to create a schizophrenic spectrum which would encompass a wider range of behaviour meaning less reliance on the presence of certain symptoms.
However, diagnosis does not provide psychiatrics with a common language, permitting communication of research ideas and findings.
Validity of diagnosis
Validity of diagnosis refers to whether the condition actaully exists or not.
ROSENHAN -"being sane in insane places" - demonstrated how easily schizophrenia is diagnosed and how the difference betwen normal and abnormal is not normally found.
This led to refinement of the diagnostic process (particularly in the USA) to include longer lasting symptoms. The first rank symptoms could be used to distinguish schizophrenia from other psychotic disorders. So one solution would have the schizophrenic spectrum to focus on severity of symptoms rather than the presence of symptoms.
Furthermore it can be asked whether schizophrenia is made up of several seperate disorders. There is no single causal factor, those diagnosed do not all show the same set of charcteristics and not everyone responds to teh same treatment.
There is also a culture bias within teh diagnosis!
WHALEY reason for greater incidence of schizophrenia among black Americans than white Americans is due to a culture bias. Ethnic differences in sxpression of symptoms are overlooked/ misinterpreted. This suggests a lack of validity in diagnosis cross culturally.
The social stigma of schizophrenia is a major obstacle in the recovery of patients with schizophrenia.
The perception of individuals with apsychotic disorder as being violent has more than doubled in prevalence since the 1950s according to Phelan et al.