Download SCHIZOPHRENIA _ TOPIC ONE: CLASSIFICATION File

Schizophrenia Topic ONE:
Classification of
schizophrenia.
WHAT YOU NEED TO KNOW:
 Positive symptoms of schizophrenia, including hallucinations and delusions.
 Negative symptoms of schizophrenia, including speech poverty and avolition.
 Reliability and validity in diagnosis and classification of schizophrenia, including
reference to co-morbidity, culture and gender bias and symptom overlap.
Clinical characteristics
Schizophrenia is a serious mental disorder affecting thought processes and the ability to
determine reality. Degree of severity varies between sufferers: some only encounter one episode, some
have persistent episodes, but live relatively normal lives through taking medication, while others have
persistent episodes, are non-responsive to medication and remain severely disturbed. Some would say that
schizophrenia may be a group of disorders, with different causes and explanations. To be diagnosed with
schizophrenia, two or more symptoms must be apparent for more than 1 month, as well as reduced social
functioning.
POSITIVE SYMPTOMS

Positive symptoms are additional to everyday experience, e.g. distortion of perception
such as hallucinations, disordered speech and delusions.
 HALLUCINATIONS: These are unusual sensory experiences. Some hallucinations are related to
events in the environment whereas others bear no relation to what the senses are picking up from
the environment, for example voices talking to or commenting on the sufferer, often criticising them
– auditory hallucinations. Also sufferer may, for example, see distorted facial expressions or
occasionally people or animals that are not there – visual hallucinations.
 DELUSIONS: Delusions are irrational beliefs. These can take a range of forms. Common delusions
involve being an important historical, political or religious figure, such as Jesus or Napoleon.
Delusions also commonly involve being persecuted, perhaps by government or aliens; these are
known as paranoid delusions. The sufferer may also believe that they have super powers.
Another class of delusions concerns the body. Sufferers may believe that they or part of them is
under external control. Delusions can make a sufferer of schizophrenia behave in ways that make
sense to them but seem bizarre to others. Although the vast majority of sufferers are not aggressive
and are in fact more likely to be victims than perpetrators of violence, some delusions can lead to
aggression.
NEGATIVE SYMPTOMS

Negative symptoms consist of a reduction or loss of normal functioning, e.g. avolition
(lack of motivation to pursue goals in life), speech poverty (lack of communication, sometimes
referred to as ‘alogia’), affective flattening (lack of emotion).
 AVOLITION: Sometimes called ‘apathy’, can be described as finding it difficult to begin or keep up
with goal-directed activity, i.e. actions performed in order to achieve a result. Sufferers of
schizophrenia often have sharply reduced motivation to carry out a range of activities. Adreason
(1982) identified three identifying signs of avolition; poor hygiene and grooming, lack of persistence
in work or education and lack of energy.
 SPEECH POVERTY: Schizophrenia is characterised by changes in patterns of speech. The ICD (10th
edition) recognises speech poverty as a negative symptom. This is because the emphasis is on
reduction in the amount and quality of speech in schizophrenia. This is sometimes accompanied by
a delay in the sufferer’s verbal responses during conversation.
The DSM places its emphasis on speech disorganisation in which speech becomes incoherent or the
speaker changes topic midsentence. This is classified in DSM-V as a positive symptom of
schizophrenia, whilst speech poverty remains a negative symptom.
Since 1994, the two main classification systems in use worldwide are DSM and the ICD
DSM-V diagnostic criteria for schizophrenia.
Characteristic symptoms: two (or more) of the following, each present for a significant portion of time during a 1-month
period (or less if successfully treated):
1. Delusions
2. Hallucinations
3. Disorganised speech (e.g. frequent derailment or incoherence)
4. Grossly disorganised or catatonic behaviour
5. Negative symptoms affective flattening (lack of emotion), alogia (lack of communication) or avolition (lack of
motivation or desire to pursue goals).
Only one criterion A symptom is required if delusions are bizarre or hallucinations consist of a voice keeping up a
running commentary on the person’s behaviour or thoughts, or two or more voices conversing with each other.
Duration: continuous signs of the disturbance persist for at least 6 months.

The above symptoms must not be due to the physiological effects of a drug of abuse or medication.
IMPORTANT: The key focus of this section is on the reliability and validity. In plain language:


Is Schizophrenia diagnosed consistently between psychiatrists and over time? (Reliability)
Is Schizophrenia a real disorder? (Validity)
Reliability of diagnosis
Reliability refers to the consistency of symptom measurement and affects classification and diagnosis in
two ways:


Test-retest reliability – occurs when a practitioner makes the same consistent diagnosis on
separate occasions from the same information.
Inter-rater reliability – occurs when several practitioners make identical, independent diagnoses
of the same patient.
Making reliable diagnoses of mental illness is problematic, as practitioners have no physical signs, but only
symptoms (mostly which the patient reports) to base decisions on.
Practitioners have to make subjective decisions due to the wording of DSM-IV – for example, comparing
patients to ‘average people’.
Research: reliability
Beck et al. (1962) reported a 54 per cent concordance rate between experienced practitioners’ diagnoses
when assessing 153 patients, while Söderberg et al (2005) reported a concordance rate of 81 per cent
using DSM-IV-TR, the most up-to-date form of the DSM classification system. This suggests that
classifications systems have become more reliable over time.
Read et al. (2004) reported a test-retest reliability of schizophrenia diagnosis to have only a 37 per cent
concordance rate, and noted a 1970 study where 194 British and 134 US psychiatrists provided a diagnosis
on the basis of a case description; 69 per cent of the Americans diagnosed schizophrenia, but only 2 per
cent of the British. This suggests that the diagnosis of schizophrenia has never been reliable.
However, Jackobsen et al. (2005) tested the reliability of the ICD-10 classification system in diagnosing
schizophrenia. A hundred Danish patients with a history of psychosis were assessed using operational
criteria, finding a concordance rate of 98 per cent, demonstrating the high reliability of clinical
diagnosis of schizophrenia using up-to-date classifications.
Reliability: general evaluation.

There are several diagnostic tools in addition to the DSM and ICD that have been
created specifically to help clinician diagnose schizophrenia (e.g. Schneider
Criteria). The use of these criteria can actually improve the reliability of diagnosis.
For example, Farmer et al. (1988) found high levels of reliability using the standard
interviewing technique known as PSE (Present State Examination).

However, the fact that different criteria have been used to diagnose schizophrenia
makes it difficult to research studies. For example, in outcome research
(investigating the outcome of treatment) it is hard to compare data based on
individuals who have been diagnosed with schizophrenia using different criteria.
Conclusion: Even if reliability of diagnosis based on classifications systems is not
perfect, they do provide practitioners with a common language, permitting
communication of research ideas and findings, which may ultimately lead to a better
understanding of the disorder and the development of effective treatments
Validity of diagnosis
Validity concerns how accurate, meaningful and useful diagnosis is. There are several ways in which validity
can be assessed:



Predictive validity: if diagnosis leads to successful treatment, the diagnosis is seen as valid.
Descriptive validity: to be valid, patients diagnosed with different disorders should differ from
each other. Descriptive validity is reduced by comorbidity, where patients have two or more
disorders simultaneously, suggesting that such disorders are not actually separate.
Criterion validity: do different assessment systems
Research: VALIDITY
Heather (1976) argued that few causes of mental disorders are known [consider this claim in the next
section on explanations of schizophrenia] and there is only a 50 per cent chance of predicting what
treatment patients will receive based on diagnosis, suggesting that diagnosis of schizophrenia is not valid.
Hollis (2000) studied 93 cases of early onset schizophrenia, applying DSM classification diagnoses to
patient case notes. The findings indicated that the diagnosis of schizophrenia had high level of stability,
suggesting that diagnoses are to a large extent valid.
CO-MORBIDITY
‘Morbidity’ refers to a medical condition or how common it is (hence we talk about morbidity rates). Comorbidity is the phenomenon that two or more conditions occur together – hence we speak of comorbidity rates. If conditions occur together a lot of the time, then this calls into question the validity of
their diagnosis and classification because they might actually be a single condition. Schizophrenia is
commonly diagnosed with other conditions. In one review Peter Buckley et al. (2009) concluded that
around half of patients with a diagnosis of schizophrenia also have a diagnosis of depression (50%) or
substance abuse (47%). Post-traumatic stress disorder also occurred in 29% of cases and OCD in 23%. This
poses a challenge for both classification and diagnosis of schizophrenia. In terms of diagnosis, if half the
schizophrenia patients are also diagnosed with depression, maybe we are just quite bad at telling the
difference between the two conditions. In terms of classification, it might me that, if very severe depression
looks a lot like schizophrenia and vice versa, then they might be better seen as a single condition
(descriptive validity). This confusing picture is a weakness of diagnosis and classification.
SYMPTOM OVERLAP
There is considerable overlap between the symptoms of schizophrenia and other conditions. For
example, both schizophrenia and bipolar disorder involve positive symptoms like delusions and negative
symptoms like avolition. This again calls into question the validity of both the classification and diagnosis of
schizophrenia. Under ICS a patient might be diagnosed as a schizophrenic; however, many of the same
patients would receive a diagnosis of bipolar according to DSM criteria. This is unsurprising given the
overlap of symptoms. It even suggests that schizophrenia and bipolar disorder may not be two different
conditions but one.
GENDER BIAS
Julia Longenecker et al. (2010) reviewed studies of the prevalence of schizophrenia and concluded that
since the 1980s men have been diagnosed with schizophrenia more often than women (prior to this there
appears to have been no difference). This may simply be because men are more genetically vulnerable
to developing schizophrenia than women. However, another possible explanation is gender bias in the
diagnosis of schizophrenia. It appears that female patients typically function better than men, being more
likely to work and have good family relationships (Cotton et al. 2009). This high functioning may explain
why some women have not been diagnosed with schizophrenia where men with similar symptoms might
have been; their better interpersonal functioning may bias practitioners to under-diagnose schizophrenia,
either because symptoms are masked altogether by good interpersonal functioning, or because the quality
of interpersonal functioning makes the case seem too mild to warrant a diagnosis.
CULTURAL BIAS
Cochrane (1977) reported the incidence of schizophrenia in the West Indies and Britain to be similar, at
around 1 per cent, but that people of African-Caribbean origin are seven times more likely to be diagnosed
with schizophrenia when living in Britain. This suggests that African-Caribbean people living in Britain
either have more stressors leading to schizophrenia, or that invalid diagnoses are being made due to
cultural bias.
Whaley (2004) believed the main reason for the incidence of schizophrenia among black Americans being
greater than among white Americans is cultural bias, where ethnic differences in symptom expression are
overlooked or misinterpreted by practitioners. This suggests a lack of validity in diagnosis.
Conclusion: Kendell and Jablensky (2007) responded to the claim that schizophrenia should be abolished
as a concept for being scientifically meaningless. They stated that diagnostic categories are justifiable
concepts, as they provide a useful framework for organising and explaining the complexity of clinical
experience, allowing clinicians to derive inferences about outcomes and to guide decisions about treatment.
Extension reading: Additional issues of classification and
diagnosis
The effects of labelling: Critics of diagnosis have suggested that it is
stigmatising to attach a ‘label’ of schizophrenia to an individual. Scheff
(1966) believed that people labelled with a diagnosis will conform to the
label and it therefore becomes a self-fulfilling prophecy. While this is clearly
and inadequate explanation for a serious mental disorder like
schizophrenia, it is nonetheless true that mental illness labels stick, and they
can be used to describe the person rather than the disorder.
Anti-psychiatry perspective (The question of whether schizophrenia is a
mental disorder at all. Mental illness as dehumanising and a form of
political control). There are those, such as Thomas Szasz, who have
questioned the whole concept of mental illness and has suggested that the
process of diagnosis is just a form of political control. He argues that
physical illness is different from mental illness.
Szasz’s main objection to the concept of mental illnesses, such as
schizophrenia, is that it dehumanises people. To say that someone is ill is to
remove responsibility from them for their problems. Szasz mounted a
strong and direct challenge to the medical model of mental disorders. His
work may have helped to give rise to the ‘patient power’ movement in the
early 1960s.
QUESTIONS:
1. Read the item and then answer the questions that follow.
Louise comes from a family with a history of schizophrenia, as both her
grandfather and an aunt have been diagnosed with the disorder. Louise’s
father has recently died from cancer and she has just moved out of the family
home to start a university course. Although she has always been healthy in
the past, she has just begun to experience symptoms of schizophrenia, such
as delusions and hallucinations.
Using your knowledge of schizophrenia, explain why Louise is now showing
symptoms of schizophrenia.
[4 marks]
2. Explain what is mean by the positive symptoms of schizophrenia [4 marks]
3. Explain the term avolition [2 marks]
4. Explain the issues of cultural bias and gender bias in the diagnosis of schizophrenia [8 marks]
5. Discuss the classification and diagnosis of schizophrenia [16 marks]