Schizophrenia revision notes
Introduction to Schizophrenia
A ‘psychosis’ (active part of schizophrenia)
- Psychosis is a term used to describe a severe mental health problem where the individual
loses contact with reality (unlike neurosis where the individual is aware that they have
problems).
- Before the 1950s, many people with schizophrenia spent most of their lives in psychiatric
hospitals. This is known as institutionalisation. New treatment methods have changed this.
- About 25% of sufferers will get better after only one episode of the illness; 50-65% will
improve, but continue to have bouts of the illness. The remainder will have persistent
difficulties (Stirling and Hellewell, 1999).
Classification
- There are a number of systems by which we can classify abnormal patterns of thinking,
behaviour and emotion into mental disorders. These systems not only classify abnormality,
but give guidance on how to diagnose them.
- The two most widely used systems of classification and diagnosis are ICD and DSM.
- ICD: World health Organisation's International Classification of Disease - recognises a range
of subtypes
- DSM: American Psychiatric Association's Diagnostic and Statistical Manual of Mental disorder
- used to also recognise the subtypes but the most recent DSM-5 have dropped these.
- These differ slightly in their classification of schizophrenia. For example, in the DSM-5
systems one of the ‘positive symptoms’ must be present for diagnosis whereas two or more
negative symptoms are sufficient under ICD.
- Both DSM-5 and ICD-10 have dropped subtypes because they tend to be inconsistent e.g.
someone with a diagnosis of paranoid schizophrenia would not necessarily show the same
symptoms a few years later.
Diagnosis - differences between DSM and ICD
- In the DSM-5 system one of the so-called positive symptoms (delusion, hallucinations or
speech disorganisation) must be present for diagnosis
- Under ICD, two or more positive symptoms must be present for a diagnosis to be made - only
one symptom is needed if the delusions are bizarre, or if the hallucinations consist of a voice
commenting on the individual’s behaviour.
Subtypes (in the ICD) of Schizophrenia
Disorganised (hebephrenic) Type
- Must have all; disorganised speech, disorganised behaviour, flat or inappropriate
affect/emotion and does not meet the criteria for Catatonic Type.
Catatonic Types
- Immobility or stupor excessive motor activity that is apparently purposeless, extreme
negativity, strange voluntary movement as evidenced by posturing, stereotyped movements,
prominent grimacing.
Paranoid Type
- Preoccupation with one or more delusions or frequent auditory hallucinations. No
disorganised speech, disorganised or catatonic behaviour, or flat or inappropriate affect.
Undifferentiated Type
- Variation between symptoms, not fitting into a particular type
Residual type
- Absence of primient delusions, hallucinations, disorganised speech, and grossly diagnosed or
catatonic behaviour. A presence of negativity symptoms.
,Symptoms
The symptoms of schizophrenia are typically divided into positive and negative
- Some symptoms are rare in normal, everyday experiences; these are known as positive
symptoms (type 1)
- Positive symptoms appear to reflect an excess or distortion of normal function (i.e. delusions
and hallucinations)
- Hallucinations - unusual sensory experiences may be distortions of reality
- Delusions - beliefs not based in reality, bizarre behaviour.
- Other symptoms are much less dramatic and can be experienced in everyday life and often
involve the loss of usual abilities and experiences (i.e. loss of energy, reduced personal
hygiene); these are known as negative symptoms (types 2).
- While the negative symptoms are less dramatic, they tend to last for longer than the positive
symptoms. Examples include:
- Speech poverty - reduced amount and poor quality of speech
- Avolition - loss of motivation, low activity
- A person may also be affected by secondary impairments such as depression, as a result of
the difficulties of living with the disorder (Davison and Neale, 2001).
Extra:
The illness usually occurs gradually and has three phases:
The prodromal (first) phase - Individual becomes withdrawn and lose interest in work, school and leisure
activities
The active phase - More obvious symptoms begin to occur: the duration of this phase can vary; for some
people it will last a few months, whereas others remain in the active phase
The residual phase - The obvious symptoms begin to subside, e.g. when treatment is given.
Mental Health Act
- Someone with schizophrenia may not realise they are ill and can refuse treatment when they
need it.
- As a result they can be admitted to hospital against their will and given treatment without their
consent under the Mental Health Act. This should only happen if their health is at risk, if they
are a danger to themselves, or if they may be a danger to others (known as sectioning
someone).
Evaluation
Reliability - consistency of diagnosis
- An important measure of reliability is inter rater reliability
- In relation to diagnosis, this means that different clinicians make identical, independent
diagnosis of the same patient
- Cheniaux et al (2009) had two psychiatrists independently diagnose 100 patients using both
DSM and ICD criteria
- However, there is evidence Osorio et al to suggest reliability has improved. Osorio et al
(2019) reported excellent reliability for the diagnosis of schizophrenia in 180 individuals using
the DSM-5. Pairs of interviews achieved inter rater reliability of +.97 and test retest reliability
of +.92
, Extra:
- Even if reliability of diagnosis based on classification systems is not perfect, they do provided
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 better treatments
- Evidence does generally suggest that reliability of diagnosis has improved as classification systems
have been updated.
Low validity - accuracy of diagnosis
- An important measure of validity is criterion validity: do different assessment systems arrive at the
same diagnosis for the same patient
- Evidence from the Cheniaux et al (2009) study found that out of the same 100 clients 68 were
diagnosed with schizophrenia under the ICD system and 39 under DSM (^)
- This suggests that it is much more likely to be diagnosed using ICD rather than DSM
- Suggesting that schizophrenia is either over diagnosed in ICD or under diagnosed in DSM
- Either way, this is poor validity - a weakness of diagnosis of schizophrenia
- However, there is contradictory evidence as Osorio et al (2019) found excellent agreement
between clinicians when they used two measures to diagnose schizophrenia both derived from the
DSM system. Meaning the criterion validity for diagnosing schizophrenia is actually good provided
it takes place within a single diagnostic system.
Co-morbidity
- Co-morbidity is the occurrence of two illnesses or conditions together
- 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
- Often people in real life have complex problems and multiple problems rather single problems or
problems one at a time
- Schizophrenia is commonly diagnosed with other conditions - Patients with schizophrenia may also
have issues with depression, substance abuse, PTSD or OCD. (Buckley et al - review found that about
half of those diagnosed with schizophrenia also had a diagnosis of depression or substance abuse)
- This is a problem for classification because it means schizophrenia may not exist as a distinct
condition, and is a problem for diagnosis as at least some people diagnosed with schizophrenia
may have unusual cases of conditions like depression.
Gender bias in diagnosis
- The tendency for diagnostic criteria to be applied differently to males and females
- Since the 1980s men have been diagnosed with schizophrenia more commonly than women (a
ratio of 1.4:1, Fischer and Buchanan 2017).
- One possible explanation for this is that women are less vulnerable than men, perhaps because of
genetic factors.
- However it seems more likely that women are underdiagnosed because they have closer
relationships and hence get support (Cotton et al. 2009). This leads to women with schizophrenia
often functioning better than men.
- This underdiagnosis is a gender bias and means women may not therefore be receiving treatment
and services that might benefit them.
Culture bias in diagnosis
- Some symptoms of schizophrenia, particularly hearing voices, have different meanings in different
cultures. For example in Haiti some people believe that voices actually are communications from
ancestors.
- British people of African Caribbean origin are up to nine times as likely to receive a diagnosis as
white British people (Pinto and Jones 2008), although people living in African Caribbean countries
are not, ruling out a genetic vulnerability. The most likely explanation for this is culture bias in
diagnosis of clients by psychiatrists from a different cultural background. This appears to lead to an
overinterpretation of symptoms in black British people (Escobar 2012).
