Download Discuss validity and reliability of diagnosis

Abnormal psychology
Concepts and diagnosis
© Hodder & Stoughton 2013
Activity
Abnormality can be defined as ‘a
psychological or behavioural state
leading to impairment of
interpersonal functioning and/or
distress to others’.
• Imagine someone with a plastic
duck on their head.
• Would you consider this person
to be abnormal or not?
• Would it matter what age or
gender they were? What their
cultural background was? What
situation this behaviour was
occurring in?
© Hodder & Stoughton 2013
Defining abnormality
• The deviation from social norms
definition sees abnormality as
behaviour that violates accepted
social rules, with these ‘rules’
changing across cultures,
genders, ages, situations etc.
• The failure to function
adequately definition sees
abnormality as an inability to
cope with day-to-day living and
focuses upon personal distress,
inappropriate behaviour,
unpredictability, irrationality,
observer discomfort, violation of
moral standards and
unconventionality.
• The deviation from ideal mental
health definition sees
abnormality as a failure to meet
criteria for perfect psychological
well-being, such as positive selfattitude, realizing one’s potential,
being independent, resisting
stress, perceiving reality and
control over one’s environment.
Read these three definitions of
abnormality and see if you can use them
to decide whether a person with a plastic
duck on their head is abnormal or not. Is
any one definition better than the
others?
© Hodder & Stoughton 2013
Command words:
The language of the learning outcomes
Learning outcome: Examine the concepts of normality and
abnormality
• Exam questions will require candidates to consider what
abnormality is in relation to different definitions and
biological/psychological approaches.
• This could be achieved by exploring the assumptions and criteria
that the different definitions and approaches are based upon.
© Hodder & Stoughton 2013
Reliability and validity of diagnosis
Reliability
Validity
•
Reliability of diagnosis refers to the
consistency of symptom
measurement.
•
Validity refers to the accuracy,
meaningfulness and usefulness of
diagnosis.
•
Reliability affects classification of
diagnosis in two ways:
•
Validity is assessed in four ways:
1. Test-re-test reliability – occurs
when a clinician makes the same
consistent diagnosis on separate
occasions using the same
information.
2. Inter-rater reliability – occurs
when several clinicians make
identical diagnoses of the same
patient, independently of each
other.
1. Reliability – a valid diagnosis
must first be reliable.
2. Predictive validity – diagnosis
leading to successful treatment is
seen as valid.
3. Descriptive validity – patients
diagnosed with different
disorders, differ from each other
in terms of classification.
4. Aetiological validity – patients
diagnosed with the same disorder,
have the same cause.
© Hodder & Stoughton 2013
Command words:
The language of the learning outcomes
Learning outcome: Discuss validity and reliability of diagnosis
• Exam questions will require candidates to describe and evaluate reliability
and validity of diagnosis.
• This could be achieved by outlining the concepts of reliability and validity
in how they apply to diagnosis, as well as using research evidence to
assess the degree to which diagnosis of mental disorders is reliable and
valid.
• Additional material relating to the reliability and validity of diagnosis could
also be incorporated, such as how reliability and validity of diagnosis have
changed over time, the development of specialist diagnostic inventories
and the reliability and validity of diagnosis of different mental disorders.
© Hodder & Stoughton 2013
Cultural considerations in diagnosis
How might the findings of
Cochrane’s study be explained?
The incidence of schizophrenia in
the Caribbean is the same as the
rest of the world, 1%, yet Cochrane
(1977) found that black people of
Caribbean origin in the UK are up to
7 times more likely to be diagnosed
as schizophrenic than native white
people in the UK.
Consider:
1.
Social stressors, such as poor
housing, low socio-economic
status, racism etc.
2.
Cultural relativism: where
definitions of abnormality
vary between cultures.
3.
The fact that clinicians who
make diagnoses in the UK
tend to be white.
© Hodder & Stoughton 2013