the DSM-III had fixed
the problem of
inter-rater validity
once and for all
AO2
WHALEY
inter-rater reliability
correlations in the diagnosis of
Sz, as low as 0.11
REJECT-there is a lack of
inter-rater reliability,
contradicting CARSON
COPELAND
69% of US psychiatrists
diagnosed Sz with only 2% of
British psychiatrists
diagnosed Sz
differences in
DSM and ICD
affect diagnosis.
AO3-DSM is
culturally biased
the degree to which
different raters give
consistent estimates
of the same
behaviour
Test-retest reliability
AO1
assesses the external
consistency of the test
WILKS ET AL
the test-retest reliability
was high when looking at
screening tests for Sz
AO2
ROSENHAN
there is difficulty in distinguishing between
normality and and abnormality, once admitted
patients became their illness
PRESCOTT ET AL
analysed test-retest of several measures of attention and
information in 14 chronic Sz patients found that performances
on these measures were stable over 6 months
this shows high
reliability
AO3-longitudinal
Validity
does the diagnosis represent something real and distinct and
measure what it claims to
comorbidity
AO1
presence of one or more additional
disorders co-occuring with a primary
disorder
BUCKLEY
comorbid depression occurs in 50% of patients, 47%
also have a lifelong diagnosis of comorbid substance
abuse, creating difficulties in the diagnosis/treatment
AO2
WEBER ET AL
morbidity and mortality from general
medical conditions are elevated among
patients with Sz compared with general
US population. >50% of those with Sz have
one or more comorbid psychiatric or
general medical conditions
Supports-more than half Sz go on to have another disorder
KESSLER ET AL
only a minority of those with mental
disorders were found to have received
professional treatment during the
proceeding 12 months. Those with
comorbid disorders - more likely to
receive treatment however comorbidiity
can affect treatment
shows that difficulties can occur
Predictive validity
AO1
the degree to which a test accurately
predicts a critereon that will occur in the
future
AO2
BENTALL ET AL
Sz is not a useful scientific category
as symptoms are also found in other
mental disorders
People with Sz don't always share
the same prognosis therefore
there is little predictive validity
HARRISON
social skills, academic
achievement and family
tolerance may influence
prognosis
All cases can be different and therefore
lacks predictive validity and test-retest
reliability is difficult to achieve