• Classi cation of schizophrenia. Positive symptoms of schizophrenia,
including hallucinations and delusions. Negative symptoms of schizophrenia, including
speech poverty and avolition. Reliability and validity in diagnosis and classi cation
of schizophrenia, including reference to co-morbidity, culture and gender bias
and symptom overlap.
• Biological explanations for schizophrenia: genetics and neural correlates, including the
dopamine hypothesis.
• Psychological explanations for schizophrenia: family dysfunction and
cognitive explanations, including dysfunctional thought processing.
• Drug therapy: typical and atypical antipsychotics.
• Cognitive behaviour therapy and family therapy as used in the treatment of schizophrenia.
Token economies as used in the management of schizophrenia.
• The importance of an interactionist approach in explaining and treating schizophrenia; the
diathesis-stress model.
Daniella Spoto
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,Diagnosis and classi cation of Schizophrenia
Professor Bleuer developed a symptomatic diagnostic for schizophrenia he called the four A’s:
Abnormal associations
Autistic behaviour and thinking
Abnormal e ect
Ambivalence
Positive symptoms
Positive symptoms of schizophrenia are additional experiences beyond those of ordinary
existence.
Hallucinations -Some hallucinations are related to events in the environment- they can be
distorted perceptions of things that are there.
Whereas others bear no relationship to what the senses are picking up in the environment.
For example voices heard, often criticism. Hallucinations can be experienced in relation to any
sense. The person may, for example see distorted facial expressions or occasionally people or
animals that are not there
Most common - auditory hallucinations hearing voices that other people cannot hear) –
patients report hearing a voice or several voices, telling them to do something (such as harm
themselves or someone else) or commenting on / criticising their behaviour.
Visual- distorting objects
Olfactory- smelling things that other people cannot smell
Tactile -eg feeling bugs that are crawling on or under the skin
Delusions - also known as paranoia, delusions are irrational beliefs. These can take a range of
forms. Common delusions involve being an important historical, political or religious gure, such
as Jesus or Napoleon.
Delusions also commonly involve being persecuted, perhaps by the government or aliens or
having superpowers.
Another class of delusions concerns the body. A person may believe they are under external
control.
Delusions can make a person behave in ways that make sense to them but seem bizarre to
others.
Paranoid (persecutory) delusions – the belief that the person is being spied upon or followed
e.g. their phone is tapped, there are video recorders hidden in their home.
Delusions of grandeur involve the in ated belief about the person’s power and importance e.g.
the person may believe they are famous or have special powers or abilities.
Delusions of reference are experienced when events in the environment appear to be directly
related to them e.g. special personal messages are being communicated through the radio or TV.
Negative symptoms
Negative symptoms of schizophrenia involve the loss of usual abilities and experiences
Speech poverty-
a reduction on the amount and quality of speech.
ff fi fl fi
, schizophrenia is characterised by changes in patterns of speech. Speech poverty is seen as a
negative symptom because the emphasis is on the reduction in the amount of speech in
schizophrenia. This is sometimes accompanied by delay in the person’s verbal responses during
conversation.
Now emphasis is placed on speech disorganisation in which speech becomes incoherent or the
speaker changes topic mid-sentence. This is classi ed as a positive symptom whereas speech
poverty remains a negative symptom.
Avolition- sometimes called ‘apathy’, this can be described as nding it di cult to begin or keep
up with goal-directed activity e.g actions performed in order to achieve a result. People with
schizophrenia often have a sharply reduced motivation to carry out a range of activities.
Andraesen (1982) identi ed 3 signs of avolition: poor hygiene, lack of persistence in work or
education and lack of energy
EVALUATION - issues in diagnosis and classi cation
Good reliability
One strength of the diagnosis of schizophrenia is its reliability. A psychotic diagnosis is said to be
reliable when di erent diagnosing clinician reach the same diagnosis for the same individual inter-
rater reliability. Prior to the DSM5 reliably for schizophrenia diagnosis was low but this has now
improved. Osorio et al report excellent reliability for the diagnosis of schizophrenia in 180
individuals using the DSM5. There is of interest achieved inter-rater reliability is of +.97 and test
retest reliability of +.92. This means that we can be reasonably sure that the diagnosis of
schizophrenia is consistently applied
Low validity
One lesson of the diagnosis of schizophrenia is its validity. One way just validity in a psychiatric
diagnosis is criterion validity. Cheniaux et al (2009) had do psychiatry and dependently assess
the same 100 clients using the DSM 4 and ICD criteria and found that 68 were diagnosed with
schizophrenia under the ICD and 39 under the DSM. Suggest schizophrenia is either over or uand
nder diagnosed according to the diagnostic system. Either way vests that criterion validity is low.
Counterpoint
In the Osorio et al study, they reported above there was excellent agreement between clinicians
when they used two measures to diagnose schizophrenia both derived from the DSM5 this means
that the criterion validity is good provided it takes place within a singe diagnostic system.
Co-morbidity
Another limitation of schizophrenia diagnosis is its co-morbidity with other conditions. If
conditions occur together a lot of the time then this calls into question the validity of their
diagnosis and classi cation because it may be a smuggle condition. Schizophrenia is commonly
diagnosed with other conditions. Buckley et al found that half of those diagnosed with
schizophrenia also had a diagnosis of depression or substance abuse. This is a problem for
classi cation because it means schizophrenia may not exist as a distinct condition and is a probe
for diagnosis as at least some people who have been diagnosed with schizophrenia may have
unusual cases of conditions like depression
Gender bias in diagnosis
A further limitation is gender bias. Since the 1980s men have been more commonly diagnosed
with schizophrenia than women by a ratio of 1.4:1 Fischer et al 2017. One possible explanation
for this is that women are less vulnerable than men possibly because of genetic factors however it
seems more likely that women are under-diagnosed because they have closer relationships and
hence get support (Cotton et al 2009) this leads to women with schizophrenia often functioning
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