Schizophrenia Flashcards
What is schizophrenia?
Schizophrenia is a mental disorder characterised by profound disruption of cognition and emotion
It is a type of psychosis in which thoughts and emotions are severely impaired
Schizophrenia affects an individuals perceptions, emotions, language and sense of self
What are positive symptoms of schizophrenia?
Positive symptoms…
- Add to everyday experience e.g. having a hallucination
- May be an excess or distortion of normal functions
- E.g. hearing. voices or feeling like someone is spying on them
What are negative symptoms?
Negative symptoms…
- Take away from everyday experience
- Make it difficult to carry on with day to day activities
- May be present without positive symptoms
- E.g. speech poverty, avolition
What are the positive symptoms of schizophrenia?
- Hallucinations
- Disorganised speech
- Delusions
What are the negative symptoms of schizophrenia?
- Speech poverty/ alogia
- Avoliotion
What are the two main classification systems used to diagnose Sz?
Who published them and where are they used?
- DSM-5: Diagnostic and Statistical Manual Edition 5, American publishers, used in USA
- ICD-10: International Classification of Disease Edition 10, used in Europe
What is the DSM-5 criteria for diagnosis of schizophrenia?
Patient has experienced one or more of the positive symptoms that has caused problems with work, relationships or personal care. Disturbances need to have lasted approx. 6 months, with at least one month of symptoms.
What are classification systems used for?
Psychiatrists used classification systems to specify symptoms that should be shown if a diagnosis of schizophrenia is to be given
Do all classification systems have the same criteria that needs to be met for diagnosis?
No, they vary in criteria
What is the ICD-10 criteria for diagnosis of schizophrenia?
Two or more negative symptoms is sufficient under the ICD-10. ICD-10 recognises subtypes of Sz e.g. catatonic Sz
EVALUATION: What is a problem with reliability then classifying schizophrenia? (DSM and ICD)
An indicator of problems with reliability comes from differences. between DSM and ICD. They use different criteria to diagnose Schizophrenia so they can be inconsistent with each other.
(Lowers reliability)
EVALUATION: What is a problem with reliability when classifying schizophrenia? (Cheniaux et al)
2 psychiatrists diagnosed 100 patients
Psychiatrist 1: diagnosed 26% with Sz using DSM and 44% using ICD
Psychiatrist 2: diagnosed 13% with Sz using DSM and 24% using ICD
This suggests you are more likely to get a diagnosis with ICD which shows that the two classification systems are not comparable/ consistent with eachother
Decreases inter-rater reliability
EVALUATION: What is a problem with reliability when classifying schizophrenia? (Copeland 1971)
There are cultural differences
Study involved 194 British psychiatrists and 134 USA psychiatrists
They were given a description of a patient to diagnose
2% of British psychiatrists diagnosed Sz
69% of USA psychiatrists diagnosed Sz
This suggests that culture may influence diagnosis which decreases the internal validity of DSM and ICD as classification systems
EVALUATION: What is a strength of reliability when classifying schizophrenia?
The classification systems (DSM and ICD) are updated overtime
This means that the information is increasingly reliable due to new research and updated findings/ theories forming the basis of the classification systems
Whilst reliability is not at it’s best, it is improving and this leads to patients receiving better diagnosis and treatment
Validity definition?
Validity is whether it measures what it claims to measure
e.g. If DSM and ICD are valid systems to classify and diagnose Schizophrenia they will measure what they claim to measure (schizophrenia)
Inter-rater reliability definition?
Consistency between different clinicians e.g. if different clinicians look at the same set of symptoms, they should give the same diagnosis
Test-retest reliability definition?
Consistency over time e.g. a person presenting the same set of symptoms should receive the same diagnosis on different occasions
EVALUATION: What is a problem with validity when classifying schizophrenia? (gender bias - Broverman et al and Longnecker et al)
Research has shown that gender bias is a problem in the diagnosis of Sz
Broverman et al argued that DSM was based on what is classified as “normal” male behaviour, therefore women may be classed as unwell because they aren’t behaving in a “male” way rather than because they are ill
Further evidence to support the existence of gender bias in diagnosis of Sz comes from Longnecker et al: found that since 1980s, more men have been diagnosed than women. They argue that this may be because women tend to show better interpersonal functioning which may mask the need for a diagnosis of Sz
Gender bias influences diagnosis in more than one way -> problem because people may not receive appropriate diagnosis and care to manage symptoms
Validity is therefore questioned
EVALUATION: What is a problem with validity when classifying schizophrenia? (symptom overlap)
Some symptoms of Sz overlap with other disorders
E.g. both Sz and bipolar disorder have positive symptoms like delusions and negative symptoms like a-volition
This means under ICD a patient may be diagnosed a schizophrenic; however, many of same patients may receive a diagnosis of bipolar disorder according to DSM criteria
This suggests the two disorders may not be two different conditions, but one
Decreases validity of the classification and diagnosis of Sz, as it fails to measure what it claims to be measuring
EVALUATION: What is a problem with validity when classifying schizophrenia? (co-morbidity - Buckley et al)
Limitation:
Research shows that there are high co-morbidity rates when diagnosing patients with Sz
Buckley et al (2009) suggested 50% of patients diagnosed with Sz also had a diagnosis of depression or 47% substance abuse. PTSD also occurred in 29% of patients, and OCD in 23%
If conditions occur, they tend to occur together a lot of the time. This then calls into question the validity of their diagnosis and classification as they might be a single condition
The diagnosis of 50% having depression and schizophrenia suggests poor understanding of the difference between the two conditions. In terms of classification, it may be that if severe depression looks like Sz, they may be better as being seen as one single condition
What is co-morbidity?
Co-morbidity refers to more than one disorders or diseases that exist alongside a primary diagnosis, which is the reason a patient gets referred and/or treated
EVALUATION: What is a problem with validity when classifying schizophrenia? (cultural bias)
Research has shown that there is cultural bias in diagnosis
African American and English people of Afro-Caribbean origin are more likely to be diagnosed with Sz than white people, even though rates of Sz are not particularly high in Africa and the West-Indies
This suggests that diagnosis is almost certainly not due to genetic vulnerability, and more to do with culture bias issues. This could be due to the African culture being more accepting of hearing voices (example of a positive symptom) due to cultural beliefs of communication with ancestors. However when reported to a psychiatrist in Western culture, this is seen as irrational
EXTRA: Javier Escobar (2012) pointed out that overwhelmingly white psychiatrists may tend to over-interpret symptoms and distrust the honesty of black people during diagnosis. Lowers generalisability (across cultures) and validity
Evidence that supports genetics (biological) explanations of Sz (Family studies - Gottesman)
Family study
Systematic investigation
As genetic similarity increases so does the probability of sharing Sz
e.g. % risk of developing Sz for different family members such as Mz twins is 48%, Dz twins is 17% , children is 13% and parents is 6%
Shows how genetic similarity and shared risk of Sz are closely related
Evidence that supports genetics (biological) explanations of Sz (Adoption Studies - Tienari et al 2000 - Finland)
Looked at 164 adoptees with biological mothers who were diagnosed with Sz, and 197 controls born to mothers without diagnosis of Sz 11 adoptees (6.7%) developed Sz compared to 4 (2%) of control adoptees Shows that children of Sz patients are still at a heightened risk of Sz if adopted into families with no Sz
Evidence that supports genetics (biological) explanations of Sz (Sz is polygenic - Ripke et al 2014)
This study was carried out at molecular level
Showed that particular genetic variations significantly increase the risk of Sz
Strengths of evidence that supports genetic explanation of Sz (biological explanation)
- drug treatment is used to help patients with Sz therefore Sz must have some link to genes APPLICATION
- multiple sources of evidence for genetic vulnerability RELIABILITY
- current genetic research gives a positive contribution into the nature/ nurture debate (how much contributes of each) which links to the interactionist explanation
Limitations of evidence that supports genetic explanation of Sz (biological explanation)
- there are a no. of factors in the environment associated with risk of Sz e.g. family dysfunction (expressed emotion - refers to level of emotion shown to a patient by carers…high levels of neg EE act as a serious source of stress for patient)
- if diagnosis isn’t correct (e.g. don’t have Sz or have a different disorder such as bipolar, which has similar positive symptoms), making a genetic link will also be false
What is the dopamine hypothesis?
Dopamine is a neurotransmitter (chemical messenger) involved in several brain systems, it appears to be involved in Sz. It has been suggested that both too little or too much dopamine might be associated with symptoms of Sz and that this may depend on the area of the brain involved
Original version of the hypothesis: definition of hypeERdopaminergia?
Concerns high levels of dopamine activity
Original version of the hypothesis: area of the brain involved?
Subcortex/ central areas e.g. Broca’s area
Original version of the hypothesis: functions of that area of the brain?
E.g. Broca’s area: speech production
Original version of the hypothesis: symptoms of Sz that may be involved?
Poverty of speech or auditory hallucinations
More recent versions of the hypothesis: definition of hypOdoperminergia?
Concerns low levels of dopamine activity
More recent versions of the hypothesis: area of the brain involved?
Prefrontal cortex
More recent versions of the hypothesis: functions of that area of the brain?
Thinking and decision making
More recent versions of the hypothesis: symptoms of Sz that may be involved?
Negative symptoms
Dopamine pathways
- mesolimbic pathway
- mesocortical pathway
Researchers have also looked at levels of dopamine in relation to pathways in the brain.
Mesolimbic: over activity and dopamine excess: associated with positive symptoms e.g. hallucinations (and some negative symptoms according to original hypothesis)
Mesocortical: dopamine deficit: associated with negative symptoms such as a-volition and apologia
Evaluation of the dopamine hypothesis: STRENGTH (drugs)
Research has shown that drugs that increase your levels of dopamine (e.g. amphetamines) produce psychotic (schizophrenic) symptoms
This is a strength because it shows there is a link between dopamine levels and psychotic symptoms
TMT drugs can control symptoms, which lends to increased RELIABILITY as there is supportive evidence
Evaluation of the dopamine hypothesis: WEAKNESS (drugs)
Clozapine is the most effective drug at reducing schizophrenic symptoms. It acts on serotonin as well as dopamine
This is negative because if drug effects both neurotransmitters, how do you know which one is the important one
Don’t know if level of serotonin or dopamine effects Sz symptoms
Questions VALIDITY as it is unfalsifiable
Evaluation of the dopamine hypothesis: WEAKNESS (high levels of dopamine could be symptom)
High levels of dopamine could be a symptom of Sz
This is a drawback because there is a problem with not knowing if it’s a cause or effect
Can’t manipulate Sz or dopamine so can’t find out
Decreases VALIDITY
Evaluation of the dopamine hypothesis: STRENGTH (anti-psychotic drugs)
Anti-psychotic drugs that reduce Sz do so by blocking this neurotransmitter to reduce the amount of it
This is a strength because it suggests dopamine levels play an important role in managing the symptoms of Sz
This increases the RELIABILITY of the dopamine hypothesis as a biological explanation of Sz
What is the neural correlates of schizophrenia?
Measurements of the brain that link/ correlate with symptoms of Sz. There are correlates for positive and negative symptoms and we can study them using brain imaging techniques such as fMRI and EEG scans
Neural correlates of negative symptoms:
- part of the brain
- symptoms linked to this area
- summary of research
- the ventral striatum
- a-volition and loss of motivation
- Juckel et al (2006) negative correlation between activity levels and severity of overall symptoms. Lower levels of activity in this area compared to controls
Neural correlates of positive symptoms:
- part of the brain
- symptoms linked to this area
- summary of research
- superior temporal gyrus and anterior cingulate gyrus
- auditory hallucinations
- Allen et al (2007) patients had to identify whether speech was theirs of someone else’s. Lower levels of activity in these areas compared to controls
However, other than the ventral striatum and the superior temporal gyrus & anterior cingulate gyrus, what is another neural mechanism linked to Sz?
What is the function of it and it’s role in Sz?
SHOWS COMPLEXITY OF SZ AND THEREFORE HARD TO EXPLAIN WITH JUST NEURAL EXPL. (ENVIRONMENTAL TOO?)
- Prefrontal cortex
- Helps logical thinking and organisation of thoughts
- Many people with Sz have lower activity in this area which could be linked to delusions and disorganised thoughts
Drug treatments (biological treatments of Sz)
The dopamine hypothesis has linked levels of dopamine (neurotransmitter) with symptoms of Sz. Therefore drug treatment aims to alter dopamine levels in order to reduce symptoms
What is the broad term for the type of drug used to treat Sz symptoms?
Anti-psychotic
How do anti-psychotic drugs work?
By affecting D2 receptors in the brain
What are the two types of anti-psychotics?
Typical anti-psychotics and a-typical anti-psychotics
Typical anti-psychotics: Chlorpromazine: Date use began Forms available Dosage How the drug affects dopamine levels Symptoms treated and beneficial effects Side effects (short and long term)
- 1950s
- Tablets, syrup (effective quicker), injection
- Orally administrated daily: 400-800mg, maximum is 1000mg
- Dopamine levels build up, but then it’s reduced. Block dopamine receptors in the synapses of the brain reducing the action of dopamine.
- Reduces positive symptoms e.g. hallucinations. Given to anxious &/ agitated patients
- Short term: shaking muscle spasm, stiffness
- Long term: tardive dyskinesia or neural malignant syndrome
A-typical anti-psychotics: Clozapine: Date use began Forms available Dosage How the drug affects dopamine levels Symptoms treated and beneficial effects Side effects (short and long term)
- Early 1970s
- Syrups and tablets
- 300-450mg
- Block D2 receptors, but this is temporary. Also works of serotonin and glutamate receptors
- Helps cognitive symptoms e.g. depression and suicide
- Have to get regular blood tests as risk of agranulocytosis (which can be fatal)
A-typical anti-psychotics: (most recent) Risperidone: Date use began Forms available Dosage How the drug affects dopamine levels Symptoms treated and beneficial effects Side effects (short and long term)
- 1990s
- Tablets, syrups or injection that lasts about two weeks
- Small dose is given initially & this is built up to a typical daily dose of 4-8mg & a maximum of 12mg
- It binds to dopamine and serotonin receptors.
- Effective in smaller doses, without serious side effects such as that of clozapine
Why can the a-typcial anti-psychotic drug risperidone be taken in smaller doses than the a-typical anti-psychotic clozapine?
This is because it binds more strongly to dopamine receptors than clozapine does and is therefore effective in smaller doses than most anti-psychotics
What are the three key features of the psychological explanation of Sz (family dysfunction)?
- The schizophrenogenic mother
- Double binds
- Expressed emotion (EE)
Explain the schizophrenogenic mother (Fromm-Reichmann 1948)
Shcizophrenogenic means: sz causing
The characteristics of this type of mother are: cold, rejecting and controlling
The family climate tends to be tense with secrecy, this leads to distrust, which develops into paranoid delusions, which leads to Sz
