CLINICAL CHARACTERISTICS AND DIAGNOSIS OF OBSESSIVE COMPULSIVE
DISORDER
To read up on the clinical characteristics and the diagnosis of obsessive compulsive disorder, refer to
pages 514–521 of Eysenck’s A2 Level Psychology.
Ask yourself
 What are the different types of obsessive compulsive disorder (OCD)?
 What are the symptoms of OCD?
 Why does the diagnosis of OCD raise issues?
What you need to know
CLINICAL CHARACTERISTICS OF
OBSESSIVE COMPULSIVE DISORDER

The cognitive and behavioural
symptoms of OCD
ISSUES SURROUNDING THE
CLASSIFICATION AND DIAGNOSIS OF
OBSESSIVE COMPULSIVE DISORDER


In particular you must consider
the issues of reliability and
validity
Further issues you may consider
are culture bias, social issues such
as public and political attitudes to
abnormality, and the economic
implications of diagnosis
CLINICAL CHARACTERISTICS OF OBSESSIVE COMPULSIVE DISORDER
Obsessive compulsive disorder (OCD) is characterised by obsessive thinking and compulsive behaviour in
the form of rituals. It is classified as an anxiety disorder because the great majority of patients with OCD
typically experience high levels of anxiety. Patients’ obsessional thoughts create anxiety, and their
compulsive behaviour occurs to try to reduce anxiety.
Cognitive symptoms:
 The obsessions are cognitive because they consist of persistent thoughts,

impulses, or images that keep intruding into an individual’s consciousness.
For example, aggressive thoughts about loved ones or concerns about
cleanliness or security.
These obsessions can involve wishes (e.g. that an enemy would die), images
(e.g. of disturbing sexual activities), impulses (e.g. desire to attack one’s
boss), ideas (e.g. that one’s illegal actions will be discovered), or doubts (e.g.
that a crucial decision was wrong). Obsessions tend to fall into one of the
following five categories that are in order of frequency: dirt and
contamination, aggression, orderliness of inanimate objects, sex, and religion
(Akhtar et al., 1975, see A2 Level Psychology page 515).
Behavioural symptoms:
 The compulsions are behavioural symptoms because they are rigid,

repetitive actions that individuals feel compelled to perform to reduce their
anxiety level.
For example, repetitive hand-cleaning, checking doors are locked, or walking
along the cracks in the pavement. Cleaning and checking rituals are the two
most common compulsions.
Classification of Obsessive Compulsive Disorder
DSM-IV (Diagnostic and Statistical Manual, 4th edition; see A2 Level Psychology page 515), which is the
American classification system, and ICD-10 (International Classification of Diseases), the tenth edition of
which was published by the World Health Organization in 1992 (ICD-10; see A2 Level Psychology page
515), are the two most common classification systems.
According to DSM-IV-TR, the diagnosis of obsessive compulsive disorder requires the following
symptoms to be present:
 Recurrent obsessions or compulsions.
 Past or present recognition that the obsessions or compulsions are excessive

or unreasonable.
Obsessions or compulsions cause marked distress, take up more than 1 hour
a day, or interfere significantly with the individual’s normal functioning.
Within DSM-IV-TR, obsessions are defined on the basis of four criteria, all of which must be present.
1. The obsessions are recurrent and persistent and cause marked anxiety.
2. The obsessions are different from worries about real-life problems.
3. The individual tries to ignore, suppress, or neutralise obsessions with some
thought or action.
4. The individual recognises that obsessions are a product of his or her own
mind.
Within DSM-IV-TR, compulsions are defined on the basis of two criteria, both of which are required.
1. They are repetitive behaviours (e.g. hand washing, checking) or mental acts
(e.g. counting, praying) the individual feels compelled to perform in response
to an obsession or according to rigid rules.
2. They are behaviours or mental acts designed to prevent or reduce distress or
to prevent some dreaded event or situation.
ICD-10 uses similar but less detailed criteria. Obsessions and compulsions have to share all of the
following four criteria:
1. They originate in the mind of the patient.
2. They are repetitive and unpleasant, and at least one obsession or compulsion
is recognised as excessive or unreasonable.
3. The patient tries to resist his or her obsessions and compulsions.
4. The patient must experience his or her obsessive thoughts or compulsive
acts as “not pleasurable”.
ISSUES SURROUNDING THE CLASSIFICATION AND DIAGNOSIS OF OBSESSIVE
COMPULSIVE DISORDER
For any diagnostic system to work effectively, it must possess reliability and validity. Reliability means
that there is good consistency over time and between different people’s diagnosis of the same patient;
known as inter-judge (or inter-rater) reliability. If diagnosis of OCD is valid then patients who are
diagnosed as suffering from it must have the disorder. If a diagnostic system is to be valid, it must also
have high reliability. Clearly, if a disorder cannot be agreed upon (so there is low reliability) then all of the
different views cannot be correct (so there is low validity). If a diagnostic system is to be valid, it must also
have high reliability. On the other hand, a diagnostic system can be reliable but not valid—it can produce
consistently wrong diagnoses.
In terms of classification, DSM-IV and ICD-10 take a categorical approach, which assumes that all mental
disorders are distinct from each other, and that patients can be categorised with a disorder based on their
having particular symptoms. However, diagnosing abnormality is not as straightforward as this approach
suggests.
The Categorical Approach
The great majority of diagnostic systems (including DSM-IV and ICD-10) are based on categories. This is
basically an all-or-none approach—either you have a given disorder, such as obsessive compulsive
disorder, or you haven’t.
EVALUATION
 Unfortunately, reality is not as neat and tidy as suggested by these
categorical approaches. For example, what if the individual does not
recognise that their obsessions are unreasonable? This clearly doesn’t mean
that they are unreasonable.
Comorbidity
Comorbidity occurs when someone suffers from two or more different mental disorders at the same time.
RESEARCH EVIDENCE
 Steketee (1990, see A2 Level Psychology page 518) found that many patients
having obsessive compulsive disorder also suffered from one or more
personality disorders (e.g. histrionic, avoidant, schizotypal, dependent,
obsessive compulsive). Patients with OCD often have other anxiety disorders.
EVALUATION
 This suggests there is overlap between the symptoms of OCD and those of
several other disorders. This means the diagnostic categories in DSM-IV and
ICD-10 are not distinct from each other yet the classification systems assume
that they are.
 This also means that there are problems of discriminating among disorders,
so diagnosis may lack reliability and validity. Furthermore, this means OCD is
not the same disorder for all patients, making it harder to recognise and
harder to treat.
Subjectivity of Diagnosis
 Judging whether patients have any given symptom is subjective because
symptoms cannot be measured. For example, one of the criteria is that the
disorder interferes significantly with the individual’s normal functioning;
clearly there is room for subjectivity in how much the disorder has to
interfere with normal functioning for a diagnosis of OCD to be made.
 This is known as the “threshold issue”, in that does the patient cross the
threshold of significantly impaired functioning? This reduces reliability of
diagnoses because therapists sometimes disagree as to whether the
symptoms exceed the threshold.
Diagnosis: Semi-structured interviews
Patients are generally diagnosed mainly on the basis of one or more interviews with a therapist. There are
various kinds of interviews. Some are unstructured and informal, which can help to establish good rapport
between patients and therapists but reliability and validity of diagnosis tend to be low (Hopko et al., 2004,
see A2 Level Psychology page 518). The most reliable and valid approach involves the use of semistructured interviews in which patients are asked a largely predetermined series of questions.
EVALUATION
 Semi-structured interviews do have good reliability and validity. Two of
the most used semi-structured interviews for OCD are the Structured Clinical
Interview for DSM-IV-Patient Version (SCID-I/P) and the Anxiety Disorder
Interview Schedule for DSM-IV (ADIS-IV). Both interviews involve systematic
questioning about a range of symptoms common to OCD.
Good reliability and validity. The evidence suggests that it is a reasonably
reliable and valid assessment procedure (Comer, 2001, see A2 Level
Psychology page 519). Brown et al. (2001, see A2 Level Psychology page 519)
found the inter-rater agreement for OCD was excellent, indicating that this
disorder can be diagnosed with high reliability. Indeed, the reliability of
diagnosis for OCD was as high as or higher than for almost any other anxiety
disorder or type of depression. The high reliability of diagnosis is because the
compulsions of OCD are clear behavioural symptoms that make it relatively
easy for therapists to diagnose them.
 Different diagnoses and the “threshold issue”. The unreliability was
mainly due to patients reporting different symptoms during the two
interviews. The “threshold issue” also reduced reliability because therapists
sometimes disagreed as to whether the symptoms exceeded the threshold.
There was also interviewer error, in which the interviewer simply made a
mistake in categorising the patient’s responses. Steinberger and Schuch
(2002, see A2 Level Psychology page 519) found large differences between
DSM-IV and ICD-10 in their diagnoses of children and adolescents having
symptoms of OCD. Using DSM-IV criteria, 95% of the patients were diagnosed
with OCD, compared to only 46% using ICD-10 criteria. This suggests
reliability of diagnosis is an issue. They concluded that the ICD-10 criteria are
less detailed and clear than those of DSM-IV, and so the DSM-IV system is
preferable.
Culture bias and gender bias

Culture and gender bias exist when members of one ethnic group or gender are more likely to be diagnosed
than others. These biases are not evident in diagnosis of OCD as the incidence across cultures and males
and females are fairly equal.
Content validity
Any form of assessment (e.g. interview, checklist, medical records) possesses content validity if it obtains
detailed information from individual patients regarding all of the symptoms of OCD.
EVALUATION
 Semi-structured interviews can have high content validity. Assessment
procedures such as SCID-I/P and ADIS-IV have high content validity, because
they exhaustively address all the DSM-IV symptoms for OCD.
Criterion validity
The assessment of obsessive compulsive disorder possesses good criterion validity if those diagnosed with
obsessive compulsive disorder differ in predictable ways from those not receiving that diagnosis.
RESEARCH EVIDENCE
 Karno et al. (1988, see A2 Level Psychology page 520) found that patients
with obsessive compulsive disorder were more likely than healthy controls
to be divorced or separated and unemployed. Thus, there is some evidence
for criterion validity for OCD, but note that poor social and work functioning
are found in those suffering from most mental disorders and so this doesn’t
distinguish patients with OCD from patients with other mental disorders.
Construct validity
This is a type of validity that involves testing hypotheses based on the diagnosis of obsessive compulsive
disorder. For example, that patients engage in elaborate rituals is to reduce the level of anxiety caused by
their obsessional thoughts. Patients do report this to be the case and this indicates high construct validity.
EVALUATION
 A problem arises when the hypothesis is not supported. For example, if we
found that for some obsessive compulsive patients performing rituals did not
reduce their anxiety level, it would be hard to know whether this failure
occurred because the diagnosis was wrong or because the original
hypothesis was wrong.
Predictive validity
Predictive validity concerns our ability to predict the eventual outcome for patients receiving a diagnosis of
obsessive compulsive disorder.
EVALUATION
 OCD is generally regarded as a severe mental disorder that is hard to treat
effectively so it should take some time for most obsessive compulsive
patients to respond to treatment. This is the case and therefore supports
predictive validity. However, some patients with obsessive compulsive
disorder are harder to treat than others and so this reduces predictive
validity.
So what does this mean?
Overall, then, it seems that the main ways of diagnosing OCD possess reasonable content, criterion,
construct, and predictive validity. Furthermore, diagnosis of OCD tends to be more reliable than with other
disorders because the behavioural symptoms are quite clear-cut.
The two main systems of diagnosis, DSM-IV and ICD-10, and the semi-structured interviews, the
Structured Clinical Interview for DSM-IV-Patient Version (SCID-I/P) and the Anxiety Disorder Interview
Schedule for DSM-IV (ADIS-IV), have reasonably good content validity as the research findings suggest
they have sufficient detail of symptoms for accurate diagnosis. However, there are many issues that
question the reliability and validity of diagnosis, such as the categorical approach, comorbidity, and
subjectivity of diagnosis.
Unstructured clinical interviews can lack reliability and validity. However, the semi-structured interviews,
SCID-I/P and ADIS-IV, have been found to have reliability as two therapists’ diagnoses have been found to
be high in consistency, and they have high diagnostic accuracy (validity).They also seem to be relatively
free from gender and culture bias.
Over to you
1. Outline the clinical characteristics of one anxiety disorder. (5 marks)
2. Discuss the issues associated with the classification and diagnosis of one anxiety disorder. (20 marks)