CLINICAL CHARACTERISTICS AND DIAGNOSIS OF SCHIZOPHRENIA
To read up on clinical characteristics and diagnosis of schizophrenia, refer to pages
378–386 of Eysenck’s A2 Level Psychology.
Ask yourself
 What are the difficulties in diagnosing schizophrenia?
 What are the symptoms of schizophrenia?
 Can we distinguish the sane from the insane?
What you need to know
CLINICAL CHARACTERISTICS OF
SCHIZOPHRENIA

The physical and psychological
symptoms of schizophrenia
including the positive and
negative symptoms and the types
of schizophrenia
ISSUES SURROUNDING THE
CLASSIFICATION AND DIAGNOSIS OF
SCHIZOPHRENIA

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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
Schizophrenia is a psychotic disorder because it involves a loss of contact with
reality (sufferers cannot distinguish between inner experience and external reality)
and a lack of self-insight (sufferers do not realise or accept that they are ill). It is
based on two Greek words: schizo meaning “split” and phren meaning “mind”, which
refers to the splitting of the normal associations between mental processes such as
perception, cognition, and emotion.
CLINICAL CHARACTERISTICS OF SCHIZOPHRENIA
The onset of schizophrenia is typically between the late teens and the mid-30s.
About 1% of the population across cultures suffers from schizophrenia during their
lives. The symptoms vary somewhat but typically include problems with attention,
thinking, social relationships, motivation, and emotion.
Physical and Psychological Symptoms of Schizophrenia
Physical/behavioural symptoms:
 Schizophrenics may experience psychomotor poverty (lack of movement)
and in extreme cases catatonia, when awkward postures are assumed and
the schizophrenic remains motionless in this position for hours at a time.
They can exhibit “waxy flexibility” during which their body can be
manipulated into different positions.
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Schizophrenics may fall into a catatonic stupor, during which they lie
motionless and appear unaware of their surroundings but are fully conscious
throughout.
Or increased motor activity can occur, such as stereotypy, purposeless, and
repetitive movement.
Disorganised, chaotic, and bizarre behaviour can be linked to other
symptoms, e.g. covering up all the windows with black paper as a result of
cognitive disturbance.
Perceptual symptoms:
 Hallucinations: auditory hallucinations are most common, when the
schizophrenic hears voices that are often abusive or offer a critical running
commentary on their behaviour.
 Visual, smell, and taste hallucinations may also be experienced but are less
common.
Cognitive symptoms:
Thought disorders include delusions and thought interference.
 Delusions of grandeur, persecution, paranoia, and control (sometimes known
as alien control symptoms as the schizophrenic believes that their behaviour
is under external control) can occur, which can develop during the course of
the illness into an increasingly complex web of delusion.
 Thought insertion (belief that ideas are being planted in their mind),
withdrawal (belief that thoughts are being removed from their mind), and
broadcasting (belief that others can “tune into” their thoughts) can occur—
these are collectively known as thought interference symptoms.
 Cognitive impairments include intellectual deficits in learning and memory.
 Most evident are the language impairments such as repeating sounds
(echolalia), inventing words (neologisms), jumbled speech (word salad), and
nonsensical rhyming (clang associations). The speech is characterised by
incoherence and abrupt changes of topic due to cognitive distractibility
(inability to maintain a train of thought).
Social symptoms:
Schizophrenics usually show social withdrawal and may have always lacked social
skills. They have little interest in social interactions and do not gain pleasure from
them, and so may be aloof, reclusive, and emotionally distant even before the onset
of the disorder.
Emotional/mood symptoms:
 Symptoms can include a lack of emotion (emotional blunting) or
inappropriate affect (e.g. giggling when told of bereavement).
 One third of patients suffer depressive symptoms and one in eight patients
meet the criteria for a mood disorder as well as schizophrenia and so tend to
be diagnosed with schizo-affective disorder. Apathy and a lack of drive,
interest, personal care, and hygiene are common and can be linked to the
depressed state.
Classification of Schizophrenia
DSM-IV (Diagnostic and Statistical Manual, 4th edition; see A2 Level Psychology page
378), 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 378), are the two
most common classification systems.
The DSM-IV diagnostic criteria are:
1. Two or more of the symptoms identified above for a period of over 1 month.
One symptom only is needed if the delusions are bizarre or if the
hallucination is critical and abusive of the individual’s behaviour.
2. The disturbance must be evident over a significant period of time, at least 6
months, including 1 month of pronounced symptoms.
3. The symptoms must have led to a failure to function in social and
occupational roles.
The ICD-10 criteria are very similar to those used in DSM-IV. The main difference
being DSM-IV requires evidence of continuous disturbance for at least 6 months,
whereas ICD-10 requires that symptoms must be present for most of the time over a
1-month period.
Types of schizophrenia
DSM-IV identifies five types of schizophrenia: disorganised, catatonic, paranoid,
undifferentiated, and residual.
Another common classification is into the positive symptoms (hallucinations,
delusions, thought disturbances) of type I schizophrenia or acute disturbance; and
the negative symptoms (lack of interest, emotion, motivation, social withdrawal) or
type II schizophrenia or chronic disturbance.
ISSUES SURROUNDING THE CLASSIFICATION AND DIAGNOSIS OF SCHIZOPHRENIA
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; the latter is known as inter-judge
(or inter-rater) reliability. If a diagnosis of schizophrenia is valid then patients who
are diagnosed as suffering from schizophrenia 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 low reliability) then all of the different views
cannot be correct (so low validity). Whereas 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.
Issues in the classification and diagnosis of schizophrenia: Comorbidity
This refers to a patient who suffers from two or more mental disorders at the same
time. Patients with schizophrenia often have other disorders such as major
depressive disorder or bipolar disorder or an anxiety disorder. Comorbidity
happens because some symptoms are the same across disorders. This creates
problems of reliability as there can be inconsistency in which disorder is diagnosed.
RESEARCH EVIDENCE
 Sim et al.’s (2006) study of 142 hospitalised schizophrenic patients, 32% of
whom had an additional mental disorder.
Issues in the classification and diagnosis of schizophrenia: The continuity approach
This suggests that there is a continuum between schizophrenia and normality.
RESEARCH EVIDENCE
 Chapman et al. (1994, see A2 Level Psychology page 381) have found evidence
for schizotypy, which is a proneness to developing psychosis (especially
schizophrenia). This supports the continuity hypothesis and reduces the
reliability with which schizophrenia is diagnosed.
The five types of schizophrenia
The five types raise issues of reliability and validity:
 Some of the types of schizophrenia have no symptoms in common, which
questions if they can be the same disorder.
 The undifferentiated schizophrenia type raises issues of reliability and
validity because it is basically a “rag bag” category for all those patients with
schizophrenia who are hard to classify. There is such diversity of symptoms
that two patients with undifferentiated schizophrenia might have no
common symptoms.
 Another issue is residual schizophrenia. There can be inconsistency in
judgements as to whether schizophrenia cases have reduced sufficiently to
be categorised as residual. It can also be difficult to decide if the patient has
recovered or still has residual schizophrenia.
Rosenhan’s (1973) research on “being sane in insane places”
RESEARCH EVIDENCE
 Rosenhan (1973, see A2 Level Psychology pages 382–383) found hospital
staff could not distinguish between the sane and the insane. This was
because they failed to detect pseudo-patients who had faked symptoms
(reported hearing indistinct voices saying “empty”, “hollow”, and “thud”) to
gain admittance to 12 different psychiatric hospitals and once admitted
behaved in a normal manner and said they had no further symptoms to the
hospital staff. Seven out of eight participants were diagnosed with
schizophrenia. This clearly questions the reliability and validity of diagnosis.
EVALUATION
 Errors made in diagnosis may not be representative of diagnosis under more
typical circumstances as psychiatrists do not expect people to fake mental
illness. Kety (1974, see A2 Level Psychology pages 382–383) has countered
this by pointing out that if a patient faked physical symptoms, then they may
similarly be mistakenly diagnosed with a physical illness.
 The psychiatrists may not have been completely convinced. The pseudopatients were given a very rare diagnosis of “schizophrenia in remission” and
most were released in a few days, which suggests the psychiatrists were
unconvinced that the patients had really suffered from schizophrenia.
Content validity
This refers to the extent to which an assessment measure covers the range of
symptoms of schizophrenia. Thus, the diagnostic manuals have content validity if
they provide detailed information regarding all of the symptoms of schizophrenia.
RESEARCH EVIDENCE
 Jakobsen et al. (2005, see A2 Level Psychology pages 383–384) used the
Operational Criteria Checklist (OPCRIT), a symptom checklist with a glossary
providing clear and explicit descriptions of the symptoms, to study patients
with a history of psychosis. There was good agreement on the diagnosis of
schizophrenia when the diagnoses of OPCRIT were compared against those
of ICD-10, indicating a high level of reliability.
EVALUATION
 There was also good agreement (and thus high reliability) when ICD-10
and DSM-IV diagnoses were compared. Both of these findings support
content validity as the findings suggest they have sufficient detail of
symptoms for accurate diagnosis.
 Measures such as standard semi-structured interviews or the
Operational Criteria Checklist possess good content validity. This is
because they involve working through all of the symptoms associated with
schizophrenia and with other related mental disorders.
Criterion validity
Any form of assessment for schizophrenia possesses good criterion validity if those
diagnosed as having schizophrenia differ in predictable ways from those not
diagnosed as schizophrenic.
RESEARCH EVIDENCE
 Comer (2001, see A2 Level Psychology page 384) found that people with
schizophrenia are much less likely than non-schizophrenics to be in full-time
employment and to have a strong social network.
EVALUATION
 This provides some support for criterion validity but it is not especially
convincing. This is because individuals suffering from almost any mental
disorder are more likely than healthy individuals to experience social,
relationship, and job problems, and so this doesn’t distinguish
schizophrenics from patients with other mental disorders.
Construct validity
This type of validity involves testing hypotheses based on the diagnosis of
schizophrenia.
RESEARCH EVIDENCE
 The dopamine hypothesis suggests that schizophrenia is linked to high levels
of dopamine and so if individuals with schizophrenia have high levels of
dopamine then this would provide some evidence for construct validity.
EVALUTION
 This type of validity raises issues when it is not supported. This is
because it is not clear if this is because the diagnosis is wrong or the
hypothesis is wrong.
 The genetic hypothesis offers support. The genetic hypothesis (that
schizophrenia has a genetic basis) has reasonable construct validity because
it is supported by numerous twin and family studies and genetic factors are
probably more important in the development of schizophrenia than almost
any other mental disorder.
Predictive validity
This refers to our ability to predict the eventual outcome for patients who receive a
diagnosis of schizophrenia.
RESEARCH EVIDENCE
 The predictive validity of a diagnosis of schizophrenia is reasonable, but not
good because there is too much variety in the outcomes of schizophrenia. For
example, 20% recover and never have another episode whereas 10% of
schizophrenics commit suicide (Birchwood & Jackson, 2001, see A2 Level
Psychology page 384).
EVALUATION
 Predictive validity is lowered by the fact there are so many diverse
symptoms of schizophrenia that patients’ experiences of the disorder are
very different.
 Mason et al. (1997, see A2 Level Psychology page 385) found predictive
validity was higher when a 6-month period of symptoms was used as the
basis for diagnosis because this cuts out individuals who have a brief, neverto-be-repeated psychotic disturbance.
Social class bias and culture bias
Two possible biases, social class bias and culture bias, could reduce reliability and
validity.
RESEARCH EVIDENCE FOR SOCIAL CLASS BIAS
 Keith et al. (1991, see A2 Level Psychology page 385) reported that 1.9% of
lower-class people, 0.9% of middle-class people, and only 0.4% of upperclass people were diagnosed with schizophrenia. Some experts argue that
these differences reflect social class bias. This suggests that lower-class
individuals are more likely to be diagnosed with schizophrenia than are
middle-class and upper-class individuals who present with the same
symptoms.
EVALUATION
 However, we cannot be absolutely certain that this is class bias because there
may be differences in incidence of schizophrenia across the classes.
RESEARCH EVIDENCE FOR CULTURE BIAS
 Keith et al. (1991, see A2 Level Psychology page 385) found that 2.1% of
African–Americans are diagnosed with schizophrenia, compared with 1.4%
of white Americans.
 McGovern and Cope (1987, see A2 Level Psychology page 385) found twothirds of psychotic patients held in hospitals in Birmingham were African–
Caribbean, compared with only one-third who were white and Asian.
EVALUATION
 These findings suggest culture bias, however when adverse life
circumstances such as poverty and marital separation were controlled for
there was no difference in the incidence of schizophrenia in the two groups.
So What Does This Mean?
The various symptoms and types of schizophrenia can make this a difficult disorder
to diagnose. The Schizophrenia Association of Great Britain (SAGB) uses an
umbrella as a symbol to represent schizophrenia in the sense that it is an umbrella
term that covers so many forms of mental illness. The many forms of schizophrenia
inevitably raise issues of reliability and validity in diagnosis. Yet the two main
systems of diagnosis, DSM-IV and ICD-10, 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: comorbidity; the continuity between psychosis and normality;
criterion, construct, and predictive validity; social class and culture bias; and of
course Rosenhan’s (1974) research, which questions whether we can distinguish
the sane from the insane. Remember that the issues can be questioned so don’t just
focus on the negatives in terms of diagnosis as it is not completely without reliability
and validity.
Over to you
1. Outline the clinical characteristics of schizophrenia. (5 marks)
2. Discuss the issues associated with classification and diagnosis of schizophrenia.
(20 marks)