Transcript Schizophrenia

Schizophrenia
Positive Symptoms
First Rank Symptoms
• In Britain, schizophrenia is only diagnosed in the presence of one of the following ‘first rank’
symptoms (disturbances of subjective experience as reported verbally by the individual).
1) Disturbance of thought: the belief that thoughts are being inserted into the individual’s mind
from outside (thought insertion) or removed from their mind by external forces (thought
withdrawal), or that their thoughts are being made known to others (thought broadcasting).
2) Hallucinations (the experience of sensory stimuli which are not present)
• Auditory (the most common). ‘Voices’: offer a commentary on the individual's behaviour "he
is eating his dinner";
• make disparaging remarks about him "he eats like a pig ";give him commands "put the knife
on the plate".
• ‘Voices’ may be a distortion of environmental noises (fridge or radiator noises interpreted as
whispering) or projections of the individual's own thoughts (thoughts may enter the
individual’s internal speech loop or even become spoken aloud without the individual
realising that the thoughts / speech are his own (malfunction of the feedback loop).
• Somatic e.g. experience of electric shocks to the fingertips.
Positive Symptoms
3) Delusions
(beliefs which individuals are firmly convinced are true,
regardless of evidence to the contrary). These can come in:-
•
Delusions of grandeur: the individual is someone important or powerful
(Christ, Napoleon).
• Delusions of persecution: the individual is being conspired
against/interfered with by other people or organisations (M15, the Mafia).
• Delusions of reference: the individual believes that unrelated events have
personal significance e.g. the words of a song refer to them personally.
• Other common delusions: the belief that nothing really exists and all
things are simply shadows; the belief that one has been dead for years
and it is observing the world from afar.
Negative Symptoms
Emotional Disturbance
• a) Blunting: apparent indifference to events which would normally
provoke a strong emotional reaction.
• b) Inappropriate Affect: e.g. laughing when told bad news, reacting angrily
if offered a gift.
• c) Flattened Affect: absence of emotional expression, speech is in
monotone, no mobility of facial features, vacant gaze.
Lack of Volition
• Loss of interest in the external and social world. Loss of drive.
• Inability to act, including inability to perform everyday living activities e.g.
washing, cooking.
Disordered Sense of Self
• Sufferer has little idea who he / she is and has no ego-boundaries. The
sufferer displays autism, and lives in a fantasy world, taking no notice of
the world around them.
Explanations – Biological
vs Psychological
Nature vs Nurture
Diathesis Stress Model
• No-one believes Schizophrenia is completely
caused by either genes or the environment.
• There must be an INTERACTION between the
two.
• Diathesis = Genetic tendency to develop
schizophrenia.
• Stress = Environmental “trigger” that starts it
off.
Diathesis Stress Model
• Interesting Questions:
• What is More important – nature or nurture?
• How do we separate the effects of nature and
nurture? (People who share genes tend to
share the same environment)
Biological Explanations
Genetics
Bio chemicals
Brain Structure
Genetics – Twin Studies
(AO1)
• Gottesman 1991 suggests that
schizophrenia is inherited through
genes.
• QUESTIONS:
• Why study identical twins?
• What would you expect to find?
Genetics – Family Studies
(AO1)
• Gottesman also concluded that if both
your parents suffer from
Schizophrenia, you have a 46%
chance of developing it yourself
(compared to a 1% chance of someone
selected at random will suffer)
• The more genetically similar relatives
are, the more concordance is found.
Source: Gottesman (1991)
www.psychlotron.org.uk
Schizophrenia: genetics
Genetics – Adoption Studies
(AO1)
• QUESTION:
• Why did Kety et al (1988) study
adopted people with schizophrenia?
• He found:
• 14% biological relatives developed
schizophrenia
• 2.7% adopted relatives developed
schizophrenia
• QUESTION: what does this suggest?
Molecular Biology
(AO1)
• Miyakawa et al (2003)
switched off an immune
system gene in a
mouse:
• What happened?
• How can this lead to
new drug
developments?
Evaluating Genetic Explanations
(AO2)
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Make two evaluation points about:
Family Studies
Adoption Studies
Molecular Biology
Biochemical Factors – The
Dopamine Hypothesis
• This theory claims that excessive
amounts of dopamine or an
oversensitivity of the brain to
dopamine is the cause of schizophrenia
• There are 3 pieces of evidence to
support this:
• 1. Drugs which block dopamine
(Phenothaiazines) reduce the
symptoms of schizophrenia.
The Dopamine Hypothesis • 2. L-Dopa – a drug for Parkinson’s disease
actually increases dopamine – this in turn
can produce symptoms of schizophrenia.
• 3. Post mortems of schizophrenics, show
an increase of dopamine in parts of the
brain. (Seeman 1987)
Schizophrenia & dopamine
– Schizophrenia is caused by excessive DA activity.
– This causes abnormal functioning of DAdependent brain systems, resulting in
schizophrenic symptoms
– DA can increase or decrease brain activity
depending on the system you’re looking at
psychlotron.org.uk
• The dopamine hypothesis:
The dopamine hypothesis
– Would suggest abnormally high DA activity as DBH
needed to break DA down
– Can’t rule out cause of death or post-mortem
changes as a source or error
psychlotron.org.uk
• Wise & Stein (1973) report abnormally low
levels of DBH in post-mortem studies of S
patients
The dopamine hypothesis
– Suggests a role for DA in S symptoms
– Suggests that the issue is over-sensitivity to DA
rather than excessive DA levels
psychlotron.org.uk
• Overdose of amphetamine (DA agonist) can
produce S-like symptoms. S patients have
abnormally large responses to low
amphetamine doses
The dopamine hypothesis
– Supports role of DA again, but what about 40%
who don’t respond?
– Lack of impact on negative symptoms hints at two
separate syndromes
psychlotron.org.uk
• S symptoms can be treated with DA
antagonists (e.g. chlorpromazine). These are
effective in 60% of cases with more impact on
positive symptoms.
Evaluating the Dopamine Hypothesis
(AO2)
• Write six evaluation points, examining the
evidence on your handout.
•
Brain Structure
People with
schizophrenia have
abnormally large
ventricles in the brain.
Ventricles are fluid
filled cavities. This
means that the brains
of schizophrenics are
lighter than normal.
Brain Structure Evidence
• Andreasen et 1990 – conducted a
controlled CAT scan study and
found significant enlargement of
the ventricles in schizophrenics
compared to controls.
Biological explanations
• No one is sure if there are a range of different
biological problems which together cause
schizophrenia or if there are actually different
types of schizophrenia which may have
different causes.
Two Syndrome Hypothesis - Crow 1985 –
there maybe two different types!
• Type one - genetically inherited
associated with dopamine –
characterised by positive
symptoms.
• Type Two – Neurodevelopmental
disorder – to do with Brain
structure – characterised by
negative symptoms.
Positive and Negative Symptoms
• Positive - hallucinations, delusions, racing
thoughts (high)
• Negative - apathy, lack of emotion, poor
social functioning, and cognitive disorganized
etc. (low).
Advantages of the biological model
• 1. It is scientific
• 2. It offers drug therapy
• 3. It may offer a cure
Problems with biological model
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1. There is conflicting biological evidence
2. We cannot be sure that schizophrenia is one disorder
3. We cannot prove cause and effect
4. There are alternative explanations
5. It is difficult to separate out genes from social
situations.
• 6. Genetic inheritance it is only a predictor of a
‘predisposition’ and is not a predictor of actually getting
the disorder.
• 7. Biological explanations are therefore incomplete
Psychological Explanations for
schizophrenia - Behaviourism
• Behaviourists would look not only at how
patients ‘learn’ to develop faulty behaviour
patterns but also at how they learn faulty
thinking!
Operant Conditioning & schizophrenia
• Children who do not receive reinforcement for
‘normal’ behaviour may put inappropriate
attention into irrelevant environmental cues.
• For example: paying attention to the sound of
a word rather than meaning.
• This behaviour will eventually appear ‘weird’
to others.
• These strange behaviours may be rewarded by
attention and sympathy and so are reinforced.
• This can continue until the behaviour becomes
labelled as schizophrenic. (Rosenhan)
Punishment and schizophrenia
• Another suggestion is that early experience of
punishment may lead the child to retreat into
a rewarding inner world. Others then label
them as ‘odd’ or ‘strange’. (Think MPD and Eve
White)
Social learning & schizophrenia
• Families affect social learning.
• Bizarre behaviour by parents is copied by
children.
• Parents then reinforce this behaviour, until
eventually the child acquires the label of being
‘schizophrenic’.
Evidence to support operant conditioning
& reinforcement in schizophrenia
• Ullman (1969) observed mental health nurses
in their interactions with patients and
concluded that staff actually reinforce
schizophrenic behaviour by giving more
attention to these patients – thus increasing
the likelihood of the behaviour reoccurring.
Evidence for Social learning and
schizophrenia
• Roder et al. (2002) used social skills training
techniques to help schizophrenics. The
success of training programmes in teaching
new skills and reintegrating schizophrenics
back into the community suggests that these
are social skills that schizophrenics failed to
learn in the first place.
The Cognitive Model of
Schizophrenia
• Beck explains the disorder is due to genetic,
environmental, psychosocial and cognitive
factors which all interact.
• The cognitive model of schizophrenia can,
therefore, be considered a holistic approach
to the disorder.
The Stress diathesis Model
Cognitive
• Genetic abnormalities create a predisposition
for the development of the disorder, but the
disorder only develops in response to stress.
The more stressors accumulate, the greater
the risk a susceptible person has of developing
schizophrenia.
• Stress affects the development of the
hippocampus which in turn affects cognitive
skills.
The Diathesis-Stress Model
• A person with a predisposition to develop
schizophrenia has limited cognitive resources
due to biological factors such as high
dopamine, larger ventricles and poor
hippocampus development. However, as long
as life is relatively stress-free they are able to
compensate for this and their behaviour
appears normal.
Cognitive treatments for schizophrenia
• Bradshaw 1998 (Case Study)
• Bradshaw used CBT in the long-term outpatient care
of a young woman with schizophrenia. Measures of
psychosocial functioning, severity of symptoms,
compliance with treatment and reductions in
hospital visits were used to assess change over the
3- year treatment period and at 1-year follow-up.
Results indicate considerable improvement in all
outcomes.
Evaluation for psychological explanations for
schizophrenia
• Behavioural explanations lack conviction. It is highly
unlikely we can ‘learn’ schizophrenia!
• Behaviourist explanations may explain maintenance,
or differences in ability to deal with the disorder,
rather than being a cause of the disorder
• The cognitive explanation is however more holistic and
complete (and therefore less reductionist) than either
the biological or behaviourist model
Evaluation
• Psychological models are very useful in
treatment programmes. Giving patients the
cognitive skills to deal with their disorder can
reduce the symptoms.
• Behavioural techniques can help patients fit
into the community by improving social skills.
• Cognitive / behavioural therapies are less
unethical, and have no side effects compared
to drug therapy. They are however expensive.
Evaluation
• On the other hand, some patients are just too
sick to responds to psychological therapy and
are also too sick to self report about their
experiences, making this area very difficult to
investigate with any reliability or validity.
• Psychological explanations are unlikely to lead
to a cure!