The document discusses several issues that affect the validity of diagnosing major depressive disorder (MDD), including: 1) Comorbidity with other mental illnesses like anxiety disorders can negatively impact outcomes and treatment response for depression. 2) There is debate around whether distinct subtypes of depression are valid or if they are too similar. 3) Diagnoses made by general practitioners without specialist training may be less reliable and valid compared to diagnoses by mental health specialists.

1. Learning Outcomes:
1. Identify the two main issues of validity in diagnosing MDD
2. Outline & evaluate comorbidity, concurrent, content issues of validity
3. Identify validity issues of GP diagnosis of MDD
4. Evaluate how distinct subtypes of MDD effect validity of diagnosis
5. Outline differences in classification of MDD by the ICD and DSM &
Evaluate these differences in the validity of diagnosis of MDD
6. Identify Cultural differences in diagnosis of MDD
PSYA4 Psychopathology
Depression
Issues of Validity in the
Diagnosis & Classification of Depression

2. Issues of Validity in the
Diagnosis & Classification of Major Depressive Disorder
(MDD) (Depression) (A01)
What does ‘Validity’ mean?
So what does
‘The Validity of MDD diagnosis mean?’

3. Issues of Validity in the
Diagnosis & Classification of Major Depressive Disorder
(MDD) (Depression) (A01)
1) The extent that a diagnosis represents something
that is real and distinct from other disorders.
2) The extent that a classification system such as
DSM measures what it claims to measure.
There are two main validity issues to consider:
Write these two main validity issues on a separate piece of paper –
we will keep coming back to them.

4. • Comorbidity is an important issue for the validity of diagnosis of mental illness.
• What two mental illnesses might occur at the same time?
• Research has shown that the presence of an anxiety disorder is single biggest
clinical risk for the development of depression.
• The experience of anxiety serves as a compounding stressor that leads
(especially in patients with a genetic vulnerability) to major depression.
Issues of Validity
Comorbidity (A01)
So which main validity issue does comorbidity effect?
MORBIDITY –
means disease
or illness
eg mumps
COMORBIDITY –
means 2 diseases
at the same time
Eg mumps &
chickenpox

5. Issues of Validity
Consequences of Comorbidity (A02)
• Comorbidity has been repeatedly
shown to have a negative impact on
social and occupational functioning
and poorer response to treatment
for patients with depression.
• Goodwin et al (2001) found that the
odds of having suicidal thoughts was
five times higher in patients with
MDD alone, compared to patients
with no psychiatric disorder
• However, patients with MDD
comorbid with panic disorder had
triple that ratio.
What is Panic Disorder?
What does ‘comorbidity’ mean?
Why does comorbidity effect the
validity of the depression
diagnosis?

6. • Content Validity refers to whether the items in a test are
representative of that which is being measured.
• The BDI is considered to be high in content validity because it
was constructed as a result of a consensus among mental
health clinicians concerning symptoms found among
psychiatric patients.
Issues of Validity
Content Validity (A01)
Which main validity issue does content validity effect?

7. • Concurrent validity is a measure of the extent to which a
test concurs with already existing standard ways of
assessing the characteristics in question.
• Research (eg Beck et al1988) has consistently
demonstrated concurrent validity between the BDI and
other measures of depression, such as the Hamilton
Depression Scale.
• Compare the BDI and Hamilton Depression Scales now
and assess for concurrent validity.
Issues of Validity
Concurrent Validity (A01)
Which main validity issue does concurrent validity effect?

8. They found few differences on a range of clinical, psychosocial
and treatment response variables.
McCullough et al (2003) compared 681 outpatients with various
types of depression including MDD and Dysthymia.
The diagnosis of depression requires clinicians to
differentiate among several distinct subtypes of this disorder.
Issues of Validity
Are there Distinct Types of Depression?(A02)
So why do McCullough et al (2003) suggest that
distinction between the different subtypes of depression
may not be valid?

9. • For most people, a diagnosis of depression is given by their GP.
• Van Weel-Baumgarten et al (2006) suggest that diagnoses
made by GPs (rather than secondary care ‘specialists’) are made
against a background of previous patient knowledge and so
could be biased as a result.
Issues of Validity
Are GP Diagnoses Valid?(A02)
What did Zimmerman et al (2010) & Krupinski & Tiller (2001) find
in relation to RELIABILITY of diagnosis?
Why is this also an issue for VALIDITY of diagnosis?
Why does this affect VALIDITY of diagnosis?

10. DSMVersusICD
Diagnosis = TWO out of
THREE of key symptoms
present
1) sad depressed mood
2) anhedonia
3) lack of energy
Diagnosis = ONE out of
TWO of key symptoms
present
1) sad depressed mood
2) anhedonia
Issues of Validity
DSM versus ICD for validity of diagnosis (A02)
Andrews et al (1999) demonstrated that this difference in the classification
systems does not produce a high number of discrepant diagnoses and that
therefore one system relative to the other cannot be regarded as more ‘valid’
in the diagnosis of depression
Does this
affect
Validity of
Diagnosis?

11. Evaluation: Cultural Differences in Diagnosis of
Depression (A02)
Karasz (2005) gave a vignette describing depressive symptoms to
two diverse cultural groups in New York:
37 European Americans36 South Asian Immigrants
South Asian: Identified the ‘problem’
in social and moral terms, with
suggestions for treatment
emphasising self-management and
referral to non-professional help.
European Americans:
Emphasised biological
explanations for the symptoms,
including ‘hormonal imbalance’
and ‘neurological problems’.