A2 unit 4 Clinical
Psychology
4) Content
Reliability of the diagnosis of mental disorders
Validity of the diagnosis of mental disorders
Cultural issues
Pre-reading check
• By now you should have
read pages 234-245
(Brain)
• You should be thinking
about the use of the
DSM and how reliable
and valid it is, as well as
the influence of cultural
& gender issues in the
diagnosis of mental
disorders.
Learning outcomes:
a) To be able to describe and evaluate the reliability of
the diagnosis of mental disorders.
b) To be able to describe and evaluate the validity of
the diagnosis of mental disorders.
c) To be able to describe and evaluate cultural issues in
the diagnosis of mental disorders. (in all three cases
using the findings of studies).
Diagnostic and
DSM-• The
IV
Statistical Manual of Mental
Disorder (Edition 5), was
last published in 2013.
• The DSM is produced by
the American Psychiatric
Association.
• It is the most widely used
diagnostic tool in
psychiatric institutions
around the world
ICD - 10
• There is also the International
Statistical Classification of
Diseases (known as ICD).
• It is produced by the World Health
Organisation (WHO) and is
currently in it’s 10th edition.
Overview of DSM
• Using hand out, highlight key points and complete
table in pg5 in packs
• Use text books if there is anything you are unsure about
• Thought shower in your groups, strengths and
weaknesses of the DSM
Evaluation of the DSM
Strengths
1. Allows for common diagnosis (although many
revisions) because it has stood the test of time
When 2 or more doctors use the DSM, they should
come close to the same diagnosis.
2. Evidence suggests that it is reliable ~Goldstein looked
at the reliability between DSM-II and DSM-III is (1988)
She found there was evidence of reliability within the
DSM-III (but less so between DSM-II and DSM-III)
Evaluation of the DSM
Weaknesses
1. The DSM is seen as a confirmation of the medical state
of mental disorder, as suffers are ‘patients’ and
‘treatment’ is suggested.
Mental health issues are ‘disorders’ and ‘illnesses’ so
‘cures’ are looked for.
However, it might be said that some mental disorders are
simply ways of living …. who is to say whether it is
‘illness’ or not. (e.g. schizophrenics may be trying to
get back to their normal self)
Reliability and the diagnosis of mental disorders
The DSM’s reliability rests on the question of
whether one person’s set of symptoms would lead to a
common diagnosis by different physicians
If different doctors give different diagnosis for the same
set of symptoms (e.g. for the same person), then the
diagnosis are not reliable and the treatment may not
work
Studies looking at the reliability of the DSM
Goldstein (1988)
• tested DMS-III for reliability and found that there was reliability
• looked at the effect of gender on the experience of schizophrenia
• she re-diagnosed 199 patients, originally diagnosed using DSM–II; some
differences
• she asked two other experts to re-diagnoses (single blind) a random sample of 8
of the patients using the case histories with all indication of previous diagnoses
removed
• high level of agreement/consistency of diagnosis
Goldstein (1988)
• As she realised that she was aware of her hypothesis
it was important that she asked two experts to rediagnose a random sample of 8 patients.
• She found a high level of agreement and inter-rater
reliability.
• This suggests that DSM-III is a reliable tool.
Other research exploring Reliability
• Using text books, research other studies that have explored the
reliability of the DSM
• What have these studies shown?
• look at the information about Kirk and Kutchin’s (1992) study…this is on the
handout and on this PP which will be on the Blog
Kirk and Kutchins (K&K) (1992)
• In their review paper Kirk and Kutchins argued that there are
methodological problems with the studies used to test the
reliability of the DSM up until 1992… these then limit the
generalisability of the findings.
• The studies outlined used interviews and questionnaires to
gather data; K&K argued that training and supervision of
interviews was insufficient and that they lacked the
commitment and skills to be accurate.
They also pointed out that the studies they looked at tended to
take place in specialised research settings… meaning that their
findings might not relate to clinicians in normal clinical
settings.
Generally speaking, an unreliable diagnostic tool would lack
validity…. K&K suggested the DSM could also lack validity.
Evaluation of K&K (1992) points
Points about interviewing - such as that different interviewers may
affect the situation and lead to different data – might be important
when considering generalising findings from studies
Goldstein (1988) did not, however, use interviewing to test reliability –
she used re-diagnosis using secondary data, and also found reliability
Evaluation of K&K (1992) points
The patients in the studies looked at were not all from research
settings
The ‘gamblers’ in Stinchfield’s study were on a gambling treatment
program, not in a research situation.
The patients in Brown et al.’s study were out patients in a hospital
= possible ecological validity?
Evaluation of K&K (1992) points
• K&K’s study took place before Brown et al. and Stinchfield’s studies
which showed that DSM-IV-TR could be regarded as reliable.
Possible to therefore conclud that further work has been done since
DSM-II and reliability has improved.
• Goldstein (1988), Brown et al. (2003) and Stinchfield (2003) all
provide evidence that diagnosis is reliable.
Questions: you also have questions in your pack ~
page 5 that need to be completed
1) What do these studies tell us about the reliability of the DSM in
diagnosing mental disorders?
2) How are Kirk and Kutchin’s findings different from the majority of the
other studies? What does this tell us about the reliability of the
DSM?
3) How can the reliability of the DSM be improved?
Validity and the diagnosis of mental disorders
• If the DSM were not reliable it would not be valid either.
• If a diagnosis was done again and the DSM provided a different one,
then it would not be a valid diagnosis (it would not be measuring
what it claimed to measure) so therefore reliability and validity go
together
Validity and the diagnosis of mental disorders
Outline what is meant by each of the following terms:
•
•
•
•
•
Construct validity
Etiolical validity
Concurrent validity
Predictive validity
Convergent validity
Construct validity
• If the DSM is to define mental disorders, then mental
disorders need to be operationalised. Lists of
symptoms and behaviour are the result of making a
mental disorder measurable.
• It has been argued that in operationalising a concept
such as depression, something is lost from the
understanding of the nature of the whole experience
of depression, which means that the DSM is not a
valid tool. There is a lack of construct validity, in that
the constructs drawn up, for example to represent
depression, might not be representative enough.
Etiological validity
If it has etiological validity, a group of people who have
been diagnosed with the same disorder will have the
same symptoms or factors causing it.
e.g. schizophrenia is sometimes caused by too much of
the neurotransmitter dopamine….
…..so in order to have etiological validity, people
diagnosed as schizophrenic should all have an excess
of dopamine in their brain
Concurrent validity
• For a diagnosis to have concurrent validity, symptoms
that form part of the disorder but are not part of the
actual diagnosis, should be found in those diagnosed.
e.g. schizophrenics often have problems with personal
relationships, but this is not a characteristic that is
looked at when diagnosing them according to the
classification system.
Predictive validity
• Predictive validity is present if diagnosis can lead to a
prediction of future behaviours caused by the disorder.
• If a diagnosis has predictive validity we should be able
to say whether the person is likely to recover or
whether the symptoms will continue
• It should also be possible to predict how someone with
a specific disorder will respond to specific treatments.
e.g. the drug lithium carbonate is effective for bipolar
disorder, but not effective for other mental disorders. If
a classification system has good predictive validity and
diagnoses someone with bipolar disorder, they should
respond to lithium carbonate.
Convergent validity
• Convergent validity is when a test results converges
on (gets close to) another test result that measures
the same thing.
• A correlation test would be carried out ~ If two scales
measure the same construct, for example, then a
person’s score on one should converge with (correlate
with) their score on the other.
Difference between convergent,
predictive and concurrent
• Convergent validity ~ the 2 measures should be
measuring exactly the same thing
• Predictive and concurrent can have different ways of
measuring each case