Schizophrenia Flashcards
Biological factors: Genetic basis & Candidate genes
Genetic basis: Schiz runs in families Twin studies - Identical = 48% Fraternal = 17%
Candidate genes:
Polygenic + aetiologically heterogeneous
Ripke -
37,000 patients
108 genetic variations that increase risk
Biological explanations: Dopamine Hypothesis
Dopamine is important in the functioning of several brain systems that may be implicated in the symptoms of schizophrenia
Dopamine hypothesis: Hyperdopaminergia
Hyperdopaminergia in the subcortex
Original version
High levels of dopamine in the subcortex
Poverty of speech, auditory hallucinations
Dopamine hypothesis: Hypodopaminergia
Hypodopamingeria in the cortex
Abnormal low levels of dopamine in brains prefrontal cortex
Thinking and decision making
Biological explanations: Neural Correlates
Patterns of structure or activity in the brain that occur in conjunction with an experience
Neural correlates: Negative symptoms
JUCKEL
Found lower levels of activity in ventral striatum and the severity of negative symptoms
Development of avolition
Neural correlates: Positive symptoms
ALLEN
Found the hallucination group had lower activation levels in the superior temporal gurus and anterior cingulate gyrus
Evaluation biological explanation: Genetic basis
Adoption studies show children of schizophrenia sufferers are at a heightened risk even with families with no history of schiz
Available evidence shows genetic susceptibility is important
Evaluation biological explanation: Candidate genes / Dopamine hypothesis
Genes identified by RIPKE play a role for other neurotransmitters
Dopamine may not be the only contributing neurotransmitter
Evaluation biological explanation: Neural Correlates
The brain structure may not be the cause of negative symptoms less info may pass through brain structures causing lower activity
So the existence of neural correlates contribute very little ‘causation’ information
Psychological explanations: Family dysfunction
Schizophrenogenic mother
Schizophrenogenic mother (‘Schizophrenia-causing’)
Based on accounts of patients of their childhood
Cold, rejecting, controlling
Distrust - leads to paranoid delusions
Psychological explanations: Family dysfunction
Double bind theory
Communication style within a family
Dear doing the wrong thing but receive mixed messages
Punished by withdrawal of love -> leads to disorganised thinking/emotions/paranoid delusions
RISK FACTOR NOT A CAUSE
Psychological explanations: Family dysfunction
Expressed emotion
EE to a patient from carer Sources of stress... 1. Verbal criticism 2. Hostility 3. Emotional over involvement
Primarily explanation for replaces or trigger vulnerable people
Psychological explanations: Cognitive explanations
Metarepresentation
Central control
Associated with several types of abnormal information processing
Metarepresentation - cognitive ability to recognise own intentions and actions of others
So disruption to this ability - hallucinations and delusions
Central control - cognitive ability to suppress automatic responses
Disorganised speech and thought disorder as patient cannot suppress this cognitive ability
Evaluation psychological explanations: Family disfunction
READ et al
Reviewed 46 studies of child abuse - 69% women had a diagnosis of schiz and had a history of physical/sexual abuse
Evidence to link family dysfunction
However information was gathered after the development of schiz symptoms, recall of childhood may be distorted
Questions validity of results
Evaluation psychological explanations: Cognitive explanations
STIRLING et al
Used Stroop Test found schiz patients took over twice as long, shows information processing is different to control group. Symptoms and faulty cognitions are clear but does not highlight origins of the cognitions
Can only explain proximal causes but not distal causes
Typical Antipsychotics: Chlorpromazine
1950’s
Link with chlorpromazine and the dopamine hypothesis. It acts as an antagonist in the dopamine system which reduces the action of the neurotransmitter.
It blocks dopamine receptors in the synapses normalising neurotransmission.
Reduces hallucinations
Sedative effect
Atypical Antipsychotics: Clozapine
Bonds to dopamine receptors same as chlorpromazine but also acts on serotonin and glutamate receptors
Reduce depression
Mood-enhancing (good for patients who could be suicidal)
Potentially fatal side effects
Atypical Antipsychotics: Risperidone
Bonds to dopamine and serotonin receptors and has less serious side effects than clozapine
Evaluation drug therapies: evidence
Chlorpromazine
Clozapine
Chlorpromazine
1121 patients
Showed that chlorpromazine was associated with better overall functioning and reducing symptoms. Lowered replace rate
Clozapine
MELTZER found clozapine was most effective. It is effective 30-50% of treatment resistant cases where other drugs have failed
Evaluation drug therapies: Serious side effects
Side effects range from mild to severe/fatal
Sleepiness, itchy skin
Tardive dyskinesia, NMS
Psychological therapies: CBT
Helps patients identify irrational thoughts and challenge them
Helps patients better cope with symptoms
Patients can make sense of their hallucinations/delusions by offering psychological explanations to reduce anxiety
Psychological therapies: Family therapy
Takes place with families rather than individually with patients.
Improves quality of communication and helps reduce stress
Reduces levels of expressed emotions
Forming alliances
Reduces stress
Help solve problems
Improves beliefs and behaviour toward schiz
Psychological therapies: Token Economies
Token economies manage the behaviour of patients with schiz who developed maladaptive behaviour. (Institutionalised behaviour), bad hygiene, staying in pjs all day
Improves patients quality of life
Tokens - given immediately when desirable behaviour shown (reinforcement)
Rewards - The tokens are secondary reinforcers and can be swapped for rewards
Evaluation psychological therapies: Evidence
PHAROAH
Reviewed evidence for moderate support to show that family therapy significantly reduces hospital readmissions and improves quality of life
However results were inconsistent and there were problems with the quality of evidence
Family therapy evidence is week
Evaluation psychological therapies: Not a cure
The 3 therapies do not cure schiz
Biological therapies do not cure either but reduce serveruty of symptoms
Failure to cure is a weakness
Evaluation psychological therapies: Ethical issues
Token economies raise ethical issues. Privileges become more available to patients with milder symptoms and less so for patients with severe symptoms, which could prevent them for complying with desirable behaviours. Severe patients suffer discrimination, this has in turn reduced the use of token economies.
The interactionist approach: Intro
An approach that acknowledges that there are biological, psychological and societal factors in the dev of schiz
The interactionist approach: Diathesis-stress model
Both genetic vulnerability and a stress trigger is needed for the development of schiz.
MEEHL
original model stated vulnerability was entirely genetic from a single schizogene and schizotypic personality (sensitive to stress)
If a person does not have a schizogene, no amount of stress can lead to schiz.
The interactionist approach: Diathesis-stress model modern understanding
Diathesis
Stress
Diathesis
Many genes increase genetic vulnerability
Range of factors beyond genetics, psychological trauma (trauma becomes diathesis instead of a stressor)
Stress
Modern definition is anything that risks triggering an episode of schiz. (Cannabis = stressor)
The interactionist approach: Treatment according to the model
Model is associated with Antipsychotics and CBT
It is possible to believe biological causes schiz and practise CBT to relieve symptoms
Common method in UK
Evaluation interactionist approach: Evidence
TIENARI
Studied 19,000 children adopted from mothers w schiz.
A child rearing style with high levels of criticism and conflict was implicated in the development of schiz but not with the control group
Very direct sting support for the importance of adopting interactionist approach
Evaluation interactionist approach: Model is over-simple
The classic model is very over simple (schizogene + schizotypic) multiple genes increase vulnerability and multiple sources of stress
Problem for old models but not for newer models
Evaluation interactionist approach: Combination of treatments
Usefulness of adopting approach to treat schiz. It’s not possible to use combination treatments without adopting approach
Studies show there is clear practical advantage to adopting the approach in the form of superior treatment outcomes and highlights the importance.
