Schizophrenia Flashcards
What do Clinicians use to diagnose schizophrenia?
DSM
Patients must display at least 2 of the main symptoms for at least 6 month
Define positive and negative symptoms
Positive - the addition of symptoms that were not present before
Negative - the loss of normal functions that were present before
What is deficit syndrome?
- Lasting negative symptoms
- Characterised by the presence of at least 2 negative symptoms for at least 12 months
- People with it have more pronounced cognitive deficits and poorer outcomes than patients without the syndrome
- Negative symptoms respond poorly to ‘typical’ antipsychotic treatments, but newer ‘atypical’ antipsychotics claim to be superior
Give examples of positive symptoms
Hallucinations
Delusions
Disorganised speech
Grossly disorganised behaviour
Catatonic behaviour
Describe the positive symptom: Hallucinations
- Unreal perceptions of the environment
- Usually auditory (hearing voices)
- Can be visual, olfactory (smells); or tactile (feeling as though something is touching them
Describe the positive symptom Delusions
- Bizarre beliefs
Different types - paranoid delusions: e.g. a belief that the person is being followed
- delusions of grandeur (inflated beliefs) e.g they think they are famous of have special abilities
- delusions of reference (environmental events seem related to them) e.g. the person on the TV is talking to them directly
Describe the positive symptom disorganised speech
- Abnormal thought processes
- Individual finds it hard to organise their thoughts
- May flick between topics (derailment)
- May be so bad that their speech is gibberish (word salad)
Describe the positive symptom grossly disorganised behaviour
- Inability/ lack of motivation to start a task, or complete a task they are already started
- Leads to difficulties in daily life
- Can lead a lack of personal hygiene
- May dress or act in ways that seem strange to others (e.g. wearing a thick coat in the summer)
Describe the positive symptom catatonic behaviour
- Reduced reaction to the immediate environment
- Rigid posture
- Aimless motor activity
Whats the other name for speech poverty
Alogia
Describe the negative symptom speech poverty
- Lessening of speech fluency and productivity
- Reflects slowing or blocked thoughts
- Individuals may produce fewer words on a timed verbal fluency test- does not reflect knowledge, but rather spontaneous production of words
- less complex syntax
- Associated with long illness and early onset of illness
Describe the negative symptom avolition
- Reduction of interests and desires
- Inability to initiate and persist in goal-directed behaviour
- Not just poor social function or disinterest (these may be a result of something else), but a reduction in self-initiated involvement in activities that are available to them
Describe the negative symptom affective flattening
Reduction in the range and intensity of emotional expression
- facial expressions
- voice tones
- eye contact
- body language
Deficit in prosody (patterns in language that provide extra information to the listener
- intonation
- tempo
- volume
- pauses
Describe the negative symptom anhedonia
- loss of interest or pleasure in almost all activities
- lack of reactivity to normally pleasurable stimuli
- may embrace all aspects or may be confined to a certain experience
- different types
- physical anhedonia- inability to experience physical pleasures
- social anhedonia- inability to experience pleasure from interactions with others
Give 3 biological explanations to schizophrenia
- genetic explanations
- dopamine hypothesis
- neural correlates
What are the two parts to genetic explanations to schizophrenia
- schizophrenia runs in families
- candidate genes
Describe Genetics; schizophrenia runs in families
- positive correlation between genetic similarity of family members and their shared risk of SZ- Gottesman (1991)
- MZ twins have higher concordance rates for SZ (40.4%) than DZ twins (7.4%)- Joseph (2004)
- Adopted children whose biological mother has a diagnosis of SZ are more likely to be diagnosed with SZ than adopted children with biological mothers without a diagnosis- Tienari 2000
Describe Genetics; Candidate genes
- Individual genes are associated with risk of inheritance
- Several genes appear to increase the risk, so SZ is ‘polygenic’
- Different combinations of factors can lead to the development of SZ
- Ripke 2014- compared the genetic make up of 37,000 SZ patients. to 113,000 controls. 108 separate genetic variations were associated with increased risk of SZ.
- Genes associated with increased risk included those coding for the functioning of several neurotransmitters, including dopamine
What are the three parts of the dopamine hypothesis of an explanation for SZ
Neurotransmitters
The dopamine hypotheses: Hyperdopaminergia in the subcortex- old
The dopamine hypothesis: Hypodopaminergia- new
Describe The dopamine hypothesis; neurotransmitters
- Neurotransmitters (NTs) = brain’s chemical messengers
-NTs appear to work differently in the brain of patients with SZ- dopamine in particular - Dopamine is important in the functioning of several brain systems that may be implicated in the symptoms of SZ
Describe the dopamine hypotheses; hyperdopaminergia in the subcortex (the old dopamine hypothesis)
- high levels of/ high activity of dopamine in the subcortex (central areas of the brain) may have implications for symptoms of SZ
- e.g. an excess of dopamine receptors in Broca’s area (responsible for speech production) may be associated with speech poverty or auditory hallucinations
The dopamine hypothesis; Hypodopaminergia in the cortex
(The new dopamine hypothesis)
- Goldman-Rakic 2004 identified a role of low levels of dopamine in the prefrontal cortex (responsible for thinking and decision making) in the negative symptoms or SZ.
What are the two parts of the neural correlates as an explanation to SZ?
Negative symptoms
Positive symptoms
Describe neural correlates; negative symptoms
- Avolition= loss of motivation
- Motivation involves anticipation of a reward
- Certain regions of the brain are believed to be associated with this anticipation (e.g. the ventral striatum VS)
- Abnormality within the VS may therefore be involved in the development of avolition
- Juckel found a lower level of activity in the VS of SZ patients than in controls. They also observed a negative correlation between activity levels in the VS and the severity of overall negative symptoms . Therefore, activity in the VS is a neural correlate of negative symptoms of SZ
Describe the neural correlates; positive symptoms
-Allen 2007- scanned the brains of SZ patients who experience auditory hallucinations while they identified voice clips as either their own or someone else’s voice. Compared to controls, the SZ patients had lower activation in the superior temporal gyrus (processes sound) and anterior cingulate gyrus (processes emotion). The hallucination group also made more errors than the control group. Therefore we can conclude that reduced activity in these 2 areas of the brain is a neural correlate of auditory hallucination .
A03 pros of biological explanations for schizophrenia
+ lots of evidence for genetic explanations
. Very strong evidence for genetic vulnerability to SZ from multiple sources
. Gottesman- genetic similarity is closely related to shared risk
- Tienari- biological children of SZ sufferers are still at heightened risk even when adopted into families with no history of SZ
- Ripke- particular genetic variations significantly increase the risk of SZ
- therefore, genetics do seem to play a role in the onset of SZ
- Mixed evidence for the dopamine hypothesis
- Support for the role of dopamine
. Antipsychotics (reduce dopamine) also relate to symptoms- Tauscher 2014 - However Ripke found that some of the genes they identified were implicated in the production of neurotransmitters other than dopamine (such as glutamate)
- So the dopamine hypothesis is not a complete explanation of SZ
- so the dopamine hypothesis is not a complete explanation of SZ
- Correlation-causation problem
- neural correlates are useful in flagging up particular brain systems that may not be working properly, but do not prove that unusual activity in a certain region of the brain causes a symptom. Other untested factors may be involved.
- so the existence of neural correlates in SZ tells us relatively little
- Another explanation; the role of mutation
- SZ can take place in the absence of a family history of the disorder
- This may be explained by a mutation in parental DNA, which may be caused by radiation, poison, viral infection, etc
- Brown 2002 found a positive correlation between age of a persons father (associated with increased risk of sperm mutation) and risk of SZ
. 0.7% in under 25s
. 2% in over 50s - so even within biologically explanations, we are not sure where the true cause lies
- SZ isn’t just biological
- Biological factors have a lot of evidence, but if the concordance rate of MZ twins is less than 50%, something else must be playing a part
- So psychological explanations, such as the role of the family, must be important too
- Therefore, there is too much emphasis on nature, making the explanation biologically reductionist
What are the psychological explanations for schizophrenia?
Family Dysfunction
- The Schizophrenogenic Mother
- Double-Bind Theory
- Expressed Emotion
What are the cognitive explanation for schizophrenia?
Metarepresentation
Central control
Describe Family Dysfunction: The Schizophrenogenic Mother
- Fromm-Reichmann(1948) noted that many of her patients spoke of a particular type of parent, which she called the Schizophrenogenic mother
- Characteristics of the schizophrenogenic mother: cold, rejecting, controlling, creates a family climate characterised by tension and secrecy
- Leads to distrust that later develops into paranoid delusions
Family Dysfunction: Double-Bind Theory
- Bateson (1972) emphasised the role of communication within a family as a risk factor of SZ
- The child regularly finds themselves trapped in situations where they fear doing the wrong thing, but receive mixed messaged about what this is
- When the child ‘gets it wrong’ (which is often) they are punished by withdrawal of love, which leaves the child thinking the world is confusing and dangerous, and is reflected in symptoms like disorganised thinking and paranoid delusions
Family: Dysfunction: Expressed Emotion
- The level of (usually negative) emotion expressed towards a patient by their carers
- Contains several elements
. Verbal criticism (and occasionally violence)
. Hostility, including anger and rejection
. Emotional over-involvement in the life of the patient - These high levels of EE are a serious source of stress for the patient and often cause relapse in SZ patients
- Could also be the stress that triggers the onset of SZ in already vulnerable people (e.g those with a genetic link to SZ (Diathesis-stress model)
Describe cognitive Explanations for schizo
- Cognitive explanations focus on the role of mental processes
- SZ is characterised by disruption to normal though processing, suggesting that cognition is likely to be impaired
- Frith (1992) identified 2 kinds of dysfunctional thought processing that could underlie some symptoms
. Metarepresentation
. Central control
Describe cognitive explanations: Metarepresentation
- The cognitive ability to reflect on thoughts and behaviour
- Allows us to have insight into our intentions and goals, and to interpret actions of others
- Dysfunction in Metarepresentation would disrupt out ability to recognise our behaviour and thoughts and thoughts as our own and not someone else’s
- Explains auditory hallucinations and delusions such as thought insertion (someone projecting thoughts into ones own mind)
Describe cognitive explanations: central control
- The cognitive ability to suppress automatic responses while we perform deliberate actions instead
- Inability to do this may lead to disorganised speech and thought disorder
- SZ sufferers tend to experience derailment of thoughts and spoken sentences because each word triggers association, and the patient cannot suppress automatic responses to these
A03 pros of psychological explanations + cognitive
+ Support for family dysfunction as a risk factor
.Berry-(2005)adults with insecure attachments to their primary carer are more likely to have SZ
.Read-(2008)- 69% of female and 59% of male SZ inpatients had a history of physical abuse, sexual abuse, or both during childhood
-so family dysfunction does appear to play a role in the development of SZ
-however, information about childhood experiences was gathered after SZ symptoms had developed, memories may have been distorted, weakening validity
+ Strong evidence for cognitive explanations
.stirling (2006) compared 30 SZ sufferes to 18 controls on the stroop test. Patients took twice as long to name the ink colours
- this supports the central control theory, providing validity for the explanation
A03 cons for psycho and cog explanations
- Lack of evidence for schizophrenogenic mother and double-bind theory
. Both theories are based on clinical observations of patients and assessing the patients mothers for ‘crazy-making’ characteristics - These theories also blame parents of SZ suffers, when parens are already dealign with having a child with SZ and likely the caring responsibilities too, adding unnecessary added trauma
- so these 2 theories are not appropriate nowadays
- Can’t infer causes of SZ from cognitive explanations
-Links between symptoms and faulty cognition are clear, but we do not know the origins of these cognitions
-So while cognitive theories can explain proximal causes of SZ (what causes current symptoms)< they don’t explain the distal causes (orgins of the condition) - Psychological explanations don’t consider biological factors
. Could be that both biological and psychological factors can separately produce the same symptoms
. Could be diathesis-stress model- SZ more likely due to genetic vulnerability and triggered by stress? - so psychological explanations are reductionist
What are used for biological treatments of schizo?
Drug therapies
What are the two types of drug therapies?
Typical antipsychotics- traditional
Atypical antipsychotics- second-generation
Describe Typical Antipsychotics and give an example
- Have been taken since the 1950s
- Strong link with the original dopamine hypothesis
- Typical antipsychotics act as antagonist for dopamine
- Antagonists= reduce the action of a neurotransmitter
- Dopamine antagonist work by blocking dopamine receptors in the synapses of the brain, reducing the action of dopamine
- Reduce positive symptoms
- Example: Chlorpromazine
Describe Atypical antipsychotics
- Have been used since the 1970s
- The aim of developing newer antipsychotics was to improve upon the effectiveness of drugs in suppressing the symptoms of psychosis (such as SZ). And also minimise the side effects
- Typically target a range of NTs, including dopamine and serotonin
- Claim to have an effect on negative symptoms as well as positive
- Examples: Clozapine and Risperidone
Describe the Typical Antipsychotics: Chlorpromazine
- Initially, when a patient begins taking Chlorpromazine, dopamine levels build up and then its production is reduced
- According to the dopamine hypothesis, this normalises neurotransmission in key areas of the brain, and reduced symptoms like hallucinations
- Also has a sedation effect, so is also used to calm anxious patients
Describe the Atypical Antipsychotics: Clozapine
- Clozapine binds to dopamine receptors in the same way that Chlorpromazine does, but in addition it acts on serotonin and glutamate receptors
- More effective than typical antipsychotics- reduces depression and anxiety in patients and improves cognitive functioning
- Also improves mood- important as 30-50% of SZ sufferers attempt suicide at some point
Describe the Atypical Antipsychotics: Risperidone
- Is as effective as Clozapine but safer (fewer side effects)
- Developed because Clozapine caused some deaths due to a blood condition called agranulocytosis
- Like Clozapine, Risperidone binds to dopamine and serotonin receptors
- Risperidone binds more strongly to dopamine receptors than Clozapine and is therefore effective in much smaller doses than most antipsychotics and has fewer side effects
A03 pros for biological treatments for Schizophrenia
+ Evidence for effectiveness
- lots of evidence to support that typical and atypical antipsychotics are at least moderately effective in tackling the symptoms of SZ
. Thornley found that Chlorpromazine was associated with better overall functioning and reduced symptom severity compared to a placebo. Relapse rate was lower in group taking the antipsychotic
- so antipsychotics appear to be reasonably effective
A03 cons bio treatments
- serious side effects
- Typical antipsychotics associated with- dizziness, agitation, weight gain
- Atypical antipsychotics were developed to reduce side effects but they still exist
- therefore antipsychotics are not a problem-free treatment
A03 cons of bio treatments
- Use of antipsychotics depends on the dopamine hypothesis
- Use of antipsychotics strongly linked with the original dopamine hypothesis (too much dopamine), but a lot of evidence says that this is not a complete explanation- new hypothesis not enough dopamine
- So it is not clear how antipsychotics (dopamine antagonists) can help with SZ when they reduce dopamine activity
- Modern dopamine hypothesis suggests that antipsychotics shouldn’t work
- so this has undermined the faith of some people that antipsychotics do really work
A03 con of bio treatments for schizo
- The chemical cosh argument
- Chemical cosh= drugs used to subdue patients in an institution
- Antipsychotics are used in hospital siutations to calm patients and make them easier to work with, rather than for the benefit of the patients
- While short-term use to calm patient is recommended by the National Institute for Health and Clinical Excellence, this can be seen as human rights abuse
- so there are some serious ethical issues within the use of antipsychotics in a medical setting
What are the psychological therapies for Schizophrenia
CBT
Family Therapy
Token Economies
Describe CBT as a psychological treatment for schizo
- 5 - 20 sessions
- Can occur in groups or individually
- Helps patients to identify irrational thoughts and change them
- Considers less-threatening possibilities of the patients beliefs
- Will not remove symptoms of SZ but can help them to cope with them by allowing them to make sense of how their feelings are impacted
- Just knowing where their symptoms come from can reduce patient’s anxiety
- Delusions may be challenged so the patient can learn that they’re not reality
Describe Family Therapy as a psychological treatment to schizo
- Takes place within the family environment
- Aims to improve communication between family members
- Originally based on the idea that the family as the root of the problem (double bind theory, Schizophrenogenic mother)
- Nowadays: more focused on reducing the stress in the family (expressed emotion)
- Strategies:
. Form a therapeutic alliance with all family members
. Reducing the stress of caring for a relative with SZ
. Improving the family ability to anticipate and solve problems
. Helping family members achieve a balance between caring and maintaining their own lives
. Improving the family’s beliefs about and behaviour towards SZ - These strategies reduce levels of stress and EE, while increasing the chances of patients complying with medication
- Reduces likelihood of relapse and re-admission to hospital
Describe Token Economies of psychological treatments
- Reward systems used to manage patients’ maladaptive behaviours that have developed as a result of spending long periods of time in psychiatric hospitals (e.g. spending all day in their pajamas, bad hygiene)
- Does not cure SZ but improves quality of life, meaning patients will find it easier to live outside of a hospital setting
- Tokens (e.g. coloured discs) are given immediately to patients when they have carried out a desirable behaviour as a form of operant conditioning- immediacy is important to avoid a reduced effect due to a delayed reward (delay discounting)
- Tokens have no value in themselves, but they can be swapped later for rewards
- Could be sweets, magazines, cigarettes or services (room cleaned, going on walk outside hospital)
- Tokens are secondary reinforcers- only have value once the patient has learnt that they can be exchanged for rewards
A03 pros of psychological therapies
+ There is supporting evidence for the effectiveness of psychological treatments
- eg Jauhar 2014 found that CBT has a small but significant effect on both positive and negative symptoms of SZ
- Pharoah found that family therapy significantly reduces hospital readmission and improves the quality of life for patients and their families.
- therefore, CBT and family therapy are valid ways of treating schizophrenia
A03 cons of schizophrenia
- There are issues with the evidence
- Results are inconsistent across different studies. Many small-scale studies comparing patients before and after psychological treatments have found positive results, but these studies often lack a control group,or patients are not randomly allocated to their treatment condition.
- so, the supporting evidence for psychological therapies is problematic
A03 cons of psychological therapies
- The treatments do not cure schizophrenia
- Psychological treatments improve quality of life in a number of ways. CBT allows patients to make sense of, and in some cases, challenge their symptoms
- Family therapy helps by reducing the stress of living with schizophrenia, both for the patient and the other family members. Token economies make patients’ behaviour more socially acceptable so that they can reintegrate into society
- but no treatments cure SZ so psychological treatments are weak overall
A03 cons psychological therapies
- Ethical issues
- Token economies have ethical issues
. Token economies are controversial as the rewards are more available to patients with mild symptoms, as those with severe symptoms may be unable to comply with desirable behaviours. Therefore severely ill patients are discriminated against - CBT have ethical issues
. Challenging a persons paranoia can interfere with freedom of thought. - If a patient believed that the government was highly controlling, challenging this belief could easily stray into modifying their politics.
- so therapists should be careful when challenging patients thoughts
What is the interactionist approach?
Acknowledges that there are biological, psychological and societal factors in the development of schizophrenia
- Biological factors
. Genetic vulnerability
. Neurochemical and neurological abnormality
- Psychological factors
. Stress- life events and daily hassles
What is The Diathesis Stress Model?
Diathesis= vulnerability
Stress= a negative psychological experience
- The diathesis stress model says that both vulnerability to SZ and a stress-trigger are necessary to develop SZ
- One or more underlying factors make a person particularly vulnerable to developing SZ but the onset of the condition is triggered by stress
What is Meehl’s Model Diathesis-Stress Model - original
- In the original diathesis-stress model, Meehl, 1962, the diathesis was the result of a single gene ‘schizogene’
- This led to the development of a ‘Schizoptypic personality’a characteristic of which was sensitivity to stress
- According to Meehl, if a person doesn’t have the schizogene, then no amount of stress could lead to SZ
- Carriers of the gene, however, who experience chronic stress through childhood and adolescence, particularly those with a Schizophrenogenic mother, could get SZ
What is the modern understanding of diathesis?
- We now know now there is no single ‘schizogene’ but rather many genes appear to increase genetic vulnerability slightly- Ripke
- Also, diathesis may not just be genetic but rather it could include psychological trauma
- Read- proposed a neurodevelopment model in which early trauma alters the developing brain- Early and severe enough trauma (e.g child abuse) can seriously affect brain development e.g. the hypothalamic-pituitary-adrenal (HPA) system can become over-active, making the individual more vulnerable to later stress
What is the modern understanding of stress
Originally, stress was seen as psychological, and generally related to parenting
A modern definition includes anything that risk triggering SZ
A lot of recent research has considered cannabis use as a trigger for SZ
- cannabis is a stressor because it increases SZ risk by up to 7x (likely because cannabis interferes with the dopamine system)
- however, most people who smoke cannabis do not develop SZ, there must be one or more vulnerability factors
What is the treatment according to the interactionist model
Compatible with both biological and psychological treatments
Most common combination: antipsychotics + CBT
Pros of interactionist approach
+Evidence for the role of vulnerability and t
- there is evidence to support the dual role of vulnerability and stress in the development of schizophrenia
Teinari 2004- investigated the combination of genetic vulnerability and parenting style (the trigger). Children adopted from 19,000 Finnish mothers with schizophrenia between 1960 and 1979 were followed up. Their adoptive parents were assessed for child-rearing style, and the rates of schizophrenia were compared to those in a control group of adoptees without any genetic risk. A child-rearing style characterised by high levels of criticism and conflict and low levels of empathy were implicated in the development of SZ, but only for children with high genetic risk (not in the control group). This suggests that both genetic vulnerability and family-related stress are important in developing SZ- genetically vulnerable children are more sensitive to parenting behaviour - this is very strong direct support for the importance of adopting an interactionist approach to schizo, including handing on to the idea that poor parenting is a possible source of stress
Pros of the interactionist approach
+ Support for the effectiveness of combinations of treatments
- there is support for the usefulness of adopting an interactionist approach from studies comparing the effectiveness of combinations of biological and psychological treatments for schizophrenia versus biological treatments alone
- as Turkington (2006) points out it is not really possible to use combinations of treatments without adopting an interactionist approach
- studies show an advantage to using combinations of treatments for SZ. For example, in one study by Tarrier 2004, 315 patients were randomly allocated to a medication + CBT group, medication + supportive counselling, or a control group. Patients in the 2 combination groups showed lower symptom levels than those in the control group (medication only) although there was no different in rates of hospital readmission
- studies like this show that there is a clear practical advantage to adopting an interactionist approach in the form of superior treatment outcomes, and therefore highlight the importance of taking an interactionist approach
Cons of the interactionist approach
- the original diathesis-stress model is over- simplified
The classic model of a single schizogene and schizophrenic parenting style as the major source of stress is now known to be very over-simple
Multiple genes increase vulnerability to schizophrenia, each having a small effect on its own; there is no single schizogene. Also, stress can come in many forms, including (but not limited to) dysfunctional parenting.
- therefore, vulnerability and stress do not have one singe source
In fact, it is now believed that vulnerability can be the result of early trauma as well as genetic make-up, and that stress can come in many forms including biological. In one recent study by Houston childhood sexual trauma emerged as a vulnerability factor whilst cannabis use was a trigger
- this shows that the old idea of diathesis as a biological factor and stress as a psychological factor has turned out to be overly-simple
- this is a problem for the old idea of diathesis, but not newer models
Cons of the interactionist approach
- the treatment- causation fallacy
- Tuckington argue that there is a good logical fit between the interactionist approach and using combination treatment
- however, the fact that combined treatments are more effective than either on their own does not necessarily mean the interactionist approach is correct
- similarly, the fact that drugs help does not mean schizophrenia is biological in origin.
-this error of logic is called the treatment-causation fallacy
What is co-morbidity
Why might this affect the reliability or validity of schizo diag
Two or more illnesses occur together in the same person
Eg schizo and depression
Miss other symptoms so only diagnoses 1 illness
Decreases reliability- diff doctors diagnose diff disorders
Decreases validity- criteria for diag schizo incorrect might not be two separate conditions
What is symptom overlap
How does this affect the reliability and validity of diagnoses
Symptoms of a disorder may not be unique to that disorder but may also be found in other disorders, making accurate diagnosis difficult
- decreases reliability- doctors wont agree on a diagnosis- diagnose with diff disorders
- decreases validity- if the criteria incorrectly diagnoses someone as having schizophrenia- diagnosed with wrong disorder
What is symptom overlap
Symptoms of a disorder may not be unique to that disorder but may also be found in other disorders, making accurate diagnosis difficult
Outline a reliable diagnosis
For one patient whose symptoms remain the same, different doctor give the same diagnosis consistently
For different patients with the same symptoms, one doctor gives all patients the same diagnosis consistently
Outline a valid diagnosis
Extent to which a diagnosis reflects an actual disorder so the DSM measures what it says it measures
The criteria used to make the diagnosis allow us to correctly identify people who have a particular illness
Also avoid incorrectly diagnosing those who don’t have the illness
What is inter- rater reliability?
Make the same measurement to see how similar their measurements are
Becke found that diagnoses of schizo in 1962 was 52% similar and in 2005 the diagnoses of schizo was 81%= suggests the diagnosis of schizo is becoming more reliable overtime
Outline rosenhans study for the validity of diagnosing schizophrenia
-1972
- 8 volunteers went to mental health hospital
- all mentally healthy but pretended they were hearing voices - hallucinations
- admitted into hospital and then instructed to behave normally again
- see how long it takes doctors to realise patients were not schizophrenic
Findings
- even normal behaviours interpreted as abnormal
- writing behaviour
- 1st voluntter released after 7 days
- final 52 days
- doctors in the hospital made incorrect diagnoses- doctors diagnosis lacked validity
What are the 4 issues that reduce the reliability and validity of the diagnosis of schizophrenia
- Cultural bias
- Gender bias
- Co-morbidity
- Overlap of symptoms
What is cultural bias
Researchers misrepresent the differences between cultures
Reduces reliability and validity of diagnosis as doctors use the social norms of their own culture to decide whether a patients behaviour match any of the symptoms of SZ- this can lead to over diagnosis of sz in patients from a different culture to the doctors own culture
Cultural bias study support
Cochrane
How commonly people diagnosed with schizophrenia across Britain and across the Caribbean.
- 1% in Britain
- 1% in Caribean - afro-caribean peopel 7 x more lielyl to be diagnosed with schizo due to cultural bias of dcotrs
Rate of schizo similar in both places
What is gender bias
When the differences between men and women are misrepresented
1. Alpha bias
2. Beta bias
= misdiagnosed or ignored
Diff diagnosis depending on their gender
Gender bias study support
1988 Loring and Powell whether gender affects the diagnosis the patient receives
- gave bunch of doctors descriptions of a patient- some received description that the patient was male ad some female- always same symptoms
- asked to diagnose patient
Male- 56% doctors diagnosed with SZ
Female- 20%
Displayed gender bias- alpha bias
Lacked reliability
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