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Clinical characteristics, classification and diagnosis
of depression
There are two areas covered in this pack:


Clinical characteristics of depression
Issues surrounding the classification and diagnosis of depression, including reliability and validity
We are looking at major depression which is also known as unipolar depression.
Major
depression
Issues surrounding
the classification and
diagnosis of
depression
Clinial characteristics
Symptoms
(e.g. DSM-IV & ICD10)
Concurrent
Reliability
Validity
Inter-rater and testretest
Issue of comorbidity
Cultural relativism
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Consequences of
being diagnosed
with depression
Clinical characteristics of depression
Depression is classified as an affective or mood disorder.
According to a recent survey (ONS, 2010-11) approximately 20% of adults experience symptoms of
depression with a higher proportion of women than men. The incidence is higher in divorced or
separated individuals.
Major depression is characterised by a cluster of symptoms.
Behavioural (e.g. going out less)
Physical (e.g. poor sleep, agitated)
Cognitive (e.g. negative thoughts about the self and future, suicidal thoughts)
Emotional (feelings such as low mood, guilt)
Diagnosis of depression
In order to be diagnosed with major depression, a doctor or psychiatrist would look for a cluster of
symptoms as described in one of the documents that categorise mental health criteria.
There are two well-known ones: the DSM and the ICD.
DSM-V (American Psychiatric Association, APA) - The DSM is used by psychiatrists, particularly in the
US but increasingly elsewhere, to diagnose mental illness according to clusters of symptoms.
ICD-10 (World Health Organisation, WHO) - The ICD has become similar to the DSM over time but is
intended for use by health practitioners more generally. It is also an international system for assessing
how prevalent (how much of) a disorder there is in a country with a view to reducing the amount.
DSM
At least one of the following, occurring most
days, most of the time for at least two weeks:

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Persistent sadness or low mood
Marked loss of interest or pleasure
PLUS at least five of these:
Disturbed sleep
Loss of appetite or weight
Fatigue, low energy
Agitated or slower movements
Poor concentration, hard to make decisions
Feeling worthless or inappropriate guilt
Suicidal thoughts or acts
ICD
All three of the following must be present:
 Persistent sadness or low mood present
most days, most of the time for at least
two weeks
 Loss of interest or pleasure
 Fatigue or low energy
PLUS most of the following to give a total of at
least 8:
Disturbed sleep
Loss of appetite
Poor concentration and attention
Low self-esteem and self-confidence
Feeling guilty and unworthy
Suicidal thoughts, acts or self-harm
Bleak, pessimistic views of the future
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Issues with classification and diagnosis
Validity
Validity refers to the extent to which a psychological measure can be said to be measuring what was
intended.
Concurrent validity refers to the extent of agreement between two measures taken at or about the
same time. If measures agree, then there is high concurrent validity or low if they do not agree.
Wittchen et al. (2001)
A study was carried out across Germany on a target day in 1999.
20,421 patients (aged 15-99) who attended their doctor’s surgery on that day filled out a depression
screening questionnaire, which included criteria from both the DSM and ICD.
The researchers found that 4.2% of the patients fulfilled the criteria for a major depressive episode
according to DSM-IV; considerably higher rates of 11.3% were obtained using the ICD-10 criteria.
Therefore, 2–3 times more people had symptoms of depression based on the ICD-10 criteria
compared to the DSM-IV, although most of this excess was caused by people with mild depression
according to the ICD-10.
There is general recognition in the medical community that there is a higher threshold for diagnosing
depression with DSM compared to ICD.
The 633 doctors in the study looked at the depression screening questionnaires completed by their
patients only. From looking at the questionnaires, the doctors decided whether depression was
definite or probable, or whether the patient was not depressed.
The doctors' decisions about definite or probable depression showed that 75% of all DSM and 59% of
all ICD-10 diagnoses were recognised by the treating physician as depression. However, doctors also
diagnosed definite depression in an additional 11.7% of patients who did not meet either ICD-10 or
DSM-IV criteria.
The findings of this study could be interpreted in a number of ways by reflecting on the validity of the
clinical characteristics stated in ICD and DSM or alternatively by considering whether the doctors
themselves were at fault with regard to making valid diagnoses.
Comment on the concurrent validity of ICD-10 and DSM-IV.
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Comment on what the Wittchen study may tell us about the validity of the clinical characteristics of ICD
and DSM. Make separate comments about the DSM and ICD.
Comment on what the Wittchen study may tell us about doctors’ abilities to make valid diagnoses of
depression.
Comment on the possible effect on the patients arising from the issues above.
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Reliability
A reliable diagnosis would mean that different psychiatrists should agree on what disorder a
particular person has because of the presence of pre-determined symptoms. There should be high
inter-rater reliability.
Research by Beck (1961) demonstrates this issue, he looked at the inter-rater reliability between two
psychiatrists when examining 154 patients and found that it was as low as 54% meaning there were
as many as 71 cases that they failed to diagnose in the same way.
To diagnose depression, a clinical interview is used. Here are some of the ways to test reliability.

Joint interviews – a patient is interviewed by a clinician while others
observe (either in person or by reviewing a tape). They make
independent ratings. This is a measure of inter-rater reliability.

Another measure of reliability is test-retest. The same patient is
interviewed at two different times by different interviewers.
Levels of reliability tend to be lower for test-retest even if the same questions are used. Suggest a
reason for this.
The table below shows the results from three studies assessing the reliability of the DSM for
diagnosing depression.
Study
Sample size
Type of reliability
Zanarini et al., 2000
N=52
Zanarini et al., 2001
N=45
Lobbestael et al., 2010
N=151
External reliability: 710 day test-retest
Researcher reliability:
inter–rater observed
live
Researcher reliability:
inter-rater using an
audio tape
Correlation
coefficient
0.61
0.90
0.66
Comment on the reliability of diagnosis using the DSM including the effect of the type of reliability test
used
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Even if diagnoses are reliable, they are not necessarily valid. Briefly explain why this is so.
Cultural relativism
Cultural relativism in relation to mental health refers to the belief that mental disorders need to be
understood in the context of the culture of the sufferer.
The newer versions of the ICD and DSM have tried to deal with issues of cultural relativism but
despite this the issue is still is one of the biggest controversies surrounding diagnosis and
classification.
Davidson and Neal (1994) believe that in Asian cultures, for instance, people are praised for showing
no expression of emotional turmoil. People tend to display physical symptoms of depression instead.
Kua et al (1993) reported that 72% of people in China who first presented with chest or abdominal
pains or headaches were later found to have a mental health problem.
In some countries, there is no word for ‘depression’.
Comment on the validity of classifying and diagnosing depression cross-culturally.
Comorbidity
Another issue is comorbidity, which means that individuals may have more than one disorder at the
same time. For instance, according to a survey in the US, approximately half of those diagnosed with
depression have other problems as well such as anxiety, substance abuse, ADHD and post-traumatic
stress. The difficulty for the classification systems is that these problems are listed under different
headings.
Co-morbid disorders
General anxiety disorder
Agoraphobia
Specific phobia
Social phobia
Panic disorder
Post-traumatic stress disorder
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% of people also
suffering with
depression
17%
16%
24%
27%
10%
19.5%
Based on this knowledge, comment on the potential difficulties of reaching a valid diagnosis for major
depression.
Comment on the possible effect on reliability of diagnosis.
Comment on the implication for treatment.
Consequences of being diagnosed with depression
Labelling
Being associated with the label ‘depression’ can have both positive and negative consequences for the
individual. Mental illness labels can remain even when the problem has gone. If someone breaks a
bone, the person is not considered to be ‘in remission’ (still has the problem but it has temporarily
gone away). The following issues can arise from labelling. What would each one mean for someone
with depression?
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Self-fulfilling prophecy
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Sick role
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Prejudice and discrimination
Perry (2011) points out that those close to a person, such as family or work colleagues, might support
them and relieve them of some responsibilities appropriate for the sick role. On the other hand, there
could be more rejection by acquaintances and strangers if the label is known.
Labels can have both positive and negative consequences. The label could lead to an appropriate
treatment and to being cared for. However, it could also stay with that a person once they have
recovered and influence how they perceive themselves and how they are perceived or treated socially.
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Other issues with classification and diagnosis
Benefits of diagnosis
Being diagnosed with depression has benefits – what are these benefits and how important are they?
Gender and diagnosis
Women are more likely than men to be diagnosed with depression.
Do you think this difference reflects a genuine difference in incidence of depression?
If not what could be the reasons for more women being diagnosed as men? What does this suggest about
the validity of diagnosis?
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EXAM PRACTICE AND GUIDANCE
Exam Practice: Outline the Clinical Characteristics of Depression (5 marks)
To be diagnosed with _________ depression, a person must display a persistent ______ mood for at least two
________, and ______ other symptoms including sleep disturbance, weight gain or loss, loss of _________, loss of
interest in pleasure activities, difficulty in making decisions, excessive _______for real or imagined deeds, and
thoughts of or specific plan or attempt at __________.
It is useful to see how depression affects the whole person, and the symptoms can be separated into four
categories . _______(sadness, anxiety etc), ______________(pessimism, guilt etc), ___________(low energy, crying,
neglect of personal appearance) and ____________(disturbed appetite, constipation, sleep disturbance etc.)
EXAM Q: Discuss issues related to the classification and/or diagnosis of depression. (8 plus 16 marks)
MARK SCHEME
AO1 = 8 marks
Depression is classified as an affective (mood) disorder. For AO1 credit, students need to identify issues related
to the classification and/or diagnosis of depression. The Specification directs them towards reliability and
validity of C & D so these are likely to form part of the answer. Likely material includes:
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The reliability of ICD and DSM classification systems
The reliability of diagnosis between different clinicians
The benefits of diagnosis in accessing support/treatment
The problem associated with diagnosis such as labelling and adopting a sick role
The validity of diagnosis, e.g. the problem of co-morbidity with other disorders
Culture and gender differences in symptom presentation
Depression is diagnosed by the existence of 5 symptoms which should be present for a two week period on all
or most days. Students who merely present lists of signs and symptoms of depression, (e.g. depressed mood
most of the day nearly every day, diminished interest or pleasure in activities) or who describe classification
systems are not addressing the issues surrounding diagnosis and classification. Such material can gain a mark
in the rudimentary band. However students who use symptoms effectively to discuss/illustrate issues can
receive marks across the range. Examiners should be mindful of a depth/breadth trade-off – students can
describe a few issues in detail or more issues in less detail. There is considerable overlap between the issues of
classification and diagnosis.
AO2/3 = 16 marks
Credit is awarded for a discussion of the issues identified. This is likely to focus on the importance of reliable
and valid classification & diagnosis and the consequences of unreliability etc. For example:
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Depression is often co-morbid with other disorders in adults, notably anxiety and alcoholism as well as
with illnesses such as cancer (e.g. about 27% of sufferers have social phobias). Co-morbidity occurs in
children with conduct disorders and disruptive behaviour. This is important as establishing the primary
disorder influences the treatment offered.
Diagnosis can produce benefits in access to treatment, but labelling can have negative effects, on
employment prospects, motivation etc.
Two people can be diagnosed with depression but show different symptoms with little overlap.
Gender bias - diagnoses of depression are more common in women which could reflect diagnostic bias
or the reluctance of men to present with symptoms.
Cultural differences in symptom presentation (e.g. physical/somatic presentation in non-Western
cultures).
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