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 234245 (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).
• The Diagnostic and DSMStatistical 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
IV
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 re-diagnose a random sample of 8
patients.
• She found a high level of agreement and interrater 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
– Etiological 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
Strengths – validity of diagnosis
• Evidence that the DSM is valid in its
diagnosis.
• Different mental health issues cited in the
different studies, which reinforces the
conclusion
• Likely that symptoms for disorders are well
established, given that the DSM has had
many revisions.
• Different research methods have produced
data that also match the DSM criteria.
Strengths – validity of diagnosis
• Remember - if DSM is not reliable it will
not be valid.
• Great efforts have been made to make the
DSM-IV-TR more valid, such as adding
culture-bound syndromes.
– What are culture-bound syndromes?
– You already know 1!
Weaknesses – validity of diagnosis
• co-morbidity – the state of having more than
one mental disorder – is hard to diagnose using
the DSM,
– user chooses the one closest match from lists of
symptoms and features
• splitting a mental disorder into symptoms and
features is reductionist and that a holistic
approach might be more valid
Weaknesses – validity of diagnosis
• Questionnaires and interviews produce the
findings they are searching for
– For instance, if it is well known that ‘children
with ADHD are impulsive and hyperactive’,
and teachers know which children have that
label, they will then say, ‘those children are
impulsive and hyperactive’.
• The diagnosis is self-fulfilling
Cultural issues
2 ideas…..
• Culture does not affect diagnosis – mental
disorders are ‘scientific’
– The DSM was developed in the USA and is
used widely in many other cultures.
– It is valid if mental disorders are clearly
defined with specific features and symptoms.
– Mental disorders are scientifically defined
illnesses that are explained in a scientific way.
Cultural issues
• Culture does affect diagnosis – a spiritual model
– studies have shown that culture can affect diagnosis
– e.g. symptoms that are seen in western countries as
characterising schizophrenia (such as hearing voices)
are interpreted in other countries as showing possession
by spirits, which is a positive ‘disorder’.
– Depending on cultural interpretations of what is being
measured, the DSM is not always valid.
– A clinician from one culture must be aware that a patient
from another culture is guided by their own frame of
reference
Littlewood and Lipsedge (1997)
•
Littlewood & Lipsedge (1997) have suggested there is bias in
the system, not a greater vulnerability in certain groups in
society.
•
They describe the case of Calvin, a Jamaican man arrested for
arguing with the police when a post-office clerk wrongly
believed he was cashing a stolen postal order. After he was
arrested the psychiatric report noted: “This man belongs to
Rastafarian - a mystical Jamaican cult, the members of
which think they are God-like. The man has ringlet hair, a
straggly goatee beard and a type of turban. He appears
eccentric in his appearance and very vague in answering
questions. He is an irritable character and has got arrogant
behaviour." As written by a British prison psychiatrist.
•A psychiatrist must have knowledge of cultural factors before making a diagnosis e.g. in Puerto Rican
culture believing that evil spirits can possess a person is a general belief, not schizophrenia!
When testing a non-English speaker in English, the differences in language
cause assumptions to be made.
Task …
Using resources, complete page 8 -9 in your
packs ~ skinny red and Brian are useful
On the blog there is the Ford and Widiger
study – this is looking at sex bias with
diagnosis and worth a read to add to your
research bank.