schizophrenia Flashcards
what is meant by classification of mental disorder
process of organising symptoms based on which symptoms frequently cluster together
what is schizophrenia
severe mental disorder where contact with reality and insight are impaired
what are two major systems of classification of schizophrenia
-ICD-10
-DSM-5 (American)
how many symptoms need to present for classification of SZ with DSM-5
one positive symptom
how many symptoms need to be present for classification of SZ with ICD-10
two or more negative symptoms
what are positive symptoms of SZ
atypical symptoms experienced in addition to normal experiences e.g. hallucinations and delusions
what are hallucinations
sensory experiences that have either no basis in reality or a distorted perceptions of things that are there
what are delusions
involve beliefs that have no basis in reality, e.g. a person believes they are a victim of a conspiracy
what are negative symptoms of SZ
atypical experiences that represent the loss of usual experience such as speech poverty or avolition
what is avolition
involves loss of motivation to carry out tasks and results in lowered activity levels
what is speech poverty
involves reduced frequency and quality of speech
evaluation 1- good reliability ( diagnosis and classification of SZ)
-strength
-its reliable
-A psychiatric diagnosis is said to be reliable when different diagnosing clinicians reach the same diagnosis for the same individual (inter-rater reliability) and when the same clinician reaches the same diagnosis for the same individual on two occasions (test-retest reliability).
-Osório reported excellent reliability for the diagnosis of SZ in 180 individuals using the DSM-5.
-Pairs of interviewers achieved inter-rater reliability of +. 97 and test-retest reliability of +.92.
-means that we can be reasonably sure that the diagnosis of SZ is consistently applied
evaluation 2- low validity ( classification and diagnosis of SZ)
-limitation
-low validity
-Cheniaux had two psychiatrists independently assess the same 100 clients using ICD-10 and DSM-IV criteria and found that 68 were diagnosed with schizophrenia under the ICD system and 39 under DSM.
-suggests that SZ is either over- or underdiagnosed
-this suggests that criterion validity is low
evaluation 3- counterpoint of low validity ( classification and diagnosis of SZ)
-Osório study reported above there was excellent agreement between clinicians when they used two measures to diagnose SZ from the DSM system.
-means that the criterion validity for diagnosing SZ is actually good when using the same diagnostic system
evaluation 4- co morbidity (classification and diagnosis of SZ)
-limitation
-comorbidity with other conditions.
-SZ is commonly diagnosed with other conditions.
-e.g one review found that about half of those diagnosed with SZ also had a diagnosis of depression or substance abuse
-This is a problem for classification because it means SZ may not exist as a distinct condition, -also a problem for diagnosis as at least some people diagnosed with SZ may have unusual cases of conditions like depression.
-therefore ,if conditions occur together a lot of the time then this calls into question the validity
evaluation 5- gender bias ( classification and diagnosis of SZ)
-limitation
-existence of gender bias.
-Since the 80s men have been diagnosed with SZ more commonly than women
-One possible explanation for this is that women are less vulnerable than men, perhaps because of genetic factors.
-seems more likely that women are underdiagnosed because they have closer relationships and hence get support
-This leads to women with SZ often functioning better than men.
-This underdiagnosis is a gender bias and means women may not therefore be receiving treatment and services that might benefit them
evaluation 6- culture bias (classification and diagnosis of SZ)
-limitation
-existence of culture bias.
-Some symptoms of schizophrenia, particularly hearing voices, have different meanings in different cultures E.G. in Haiti some people believe that voices actually are communications from ancestors.
-British people of African-Caribbean origin are up to nine times as likely to receive a diagnosis as white British people although people living in African -Caribbean countries are not
-most likely explanation for this is culture bias in diagnosis of clients by psychiatrists from a different cultural background.
-This appears to lead to an overinterpretation of symptoms in black British people
-means that British African-Caribbean people may be discriminated against by a culturally-biased diagnostic system
evaluation 7- symptom overlap (classification and diagnosis of SZ)
-limitation
-symptom overlap with other conditions.
- E.G. both SZ and bipolar disorder involve positive symptoms (such as delusions) and negative symptoms (such as avolition)
-SZ and bipolar disorder may not be two different conditions but variations of a single condition.
-In terms of diagnosis it means that schizophrenia is hard to distinguish from bipolar disorder
- therefore, both its classification and diagnosis are flawed
what are the two biological explanations for schizophrenia
-genetic basis
- neural correlates
family studies- genetic basis of SZ ( biological explanation of SZ)
-Family studies have confirmed that risk of schizophrenia increases in line with genetic similarity to a relative with the disorder.
-shown in Gottesman’s large-scale family study.
-e.g.someone with an aunt with schizophrenia has a 2% chance of developing it, increasing to 9% if the individual is a sibling and 48% if they are an identical twin.
-family members tend to share aspects of their environment as well as many of their genes, so the correlation represents both
-but family studies still give good support for the importance of genes in schizophrenia.
candidate genes- genetic basis of SZ (biological explanation of SZ)
-Early research in this area looked for a single genetic variation in the belief that one faulty gene could explain schizophrenia.
-it appears that a number of different genes are involved, i.e. schizophrenia is polygenic.
-The most likely genes would be those coding for neurotransmitters including dopamine
-large study by Ripke et al combined all previous data from genome-wide studies of schizophrenia.
-The genetic make-up of 37,000 people with a diagnosis of schizophrenia was compared to that of 113,000 controls,
-108 separate genetic variations were associated with slightly increased risk of schizophrenia.
-schizophrenia is aetiologically heterogeneous, i.e. different combinations of factors can lead to the condition.
the role of mutation - genetic basis of SZ (biological explanation of SZ)
-Schizophrenia can also have a genetic origin in the absence of a family history of the disorder.
-One explanation for this is mutation in parental DNA which can be caused by radiation, poison or viral infection.
-Evidence for mutation comes from positive correlations between paternal age ( increased risk of sperm mutation) and risk of schizophrenia, increasing from around 0.7% with fathers under 25 to over 2% in fathers over 50 (Brown et al).
evaluation 1- research support ( genetic basis of SZ: biological explanation of SZ)
-strength
-strong evidence base.
-Family studies such as Gottesman show that risk increases with genetic similarity to a family member with schizophrenia.
-Adoption studies such as Tienari et al show that biological children of parents with schizophrenia are at heightened risk even if they grow up in an adoptive family.
-A recent twin study by Hilker et al showed a concordance rate of 33% for identical twins and 7% for non-identical twins.
-This shows that some people are more vulnerable to schizophrenia as a result of their genetic make-up.
evaluation 2- environmental factors ( genetic basis of SZ: biological explanation of SZ)
-limitation
-there is clear evidence to show that environmental factors also increase the risk of developing schizophrenia.
-These environmental factors include both biological and psychological influences.
-Morgan et al-Biological risk factors include birth complications
and
-smoking THC-rich cannabis in teenage years (Di Forti et al ).
-Psychological risk factors include childhood trauma which leaves people more vulnerable to adult mental health problems
-Mørkved found 67% of people with schizophrenia and related psychotic disorders reported at least one childhood trauma
-This means that genetic factors alone cannot provide a complete explanation for schizophrenia.
what is meant by neural correlates
patterns of structure or activity in the brain that occur in conjunction with an experience and may be implicated in the origins of experience
the original dopamine hypothesis- neural correlates (biological explanation of SZ)
-original hypothesis was based on the discovery that drugs used to treat schizophrenia caused symptoms similar to those in people with Parkinson’s disease, a condition associated with low DA levels (Seeman ).
-Therefore schizophrenia might be the result of high levels of DA (hyperdopaminergia) in subcortical areas of the brain.
-e.g. excess of DA receptors in pathways from the subcortex to Broca’s area (responsible for speech production) may explain specific symptoms such as poverty of speech and auditory hallucinations.
updated version of dopamine hypothesis- neural correlates (biological explanation of SZ)
-Davis et al. proposed the addition of cortical hypodopaminergia
-This too can explain symptoms of schizophrenia.
-e.g. low DA in the prefrontal cortex (responsible for thinking) could explain cognitive problems i.e. negative symptoms of schizophrenia.
-It is suggested that cortical hypodopaminergia leads to subcortical hyperdopaminergia - so both high and low levels of DA in different brain regions are part of the updated version.
-it seems that both genetic variations and early experiences of stress, both psychological and physical, make some people more sensitive to cortical hypodopaminergia and hence subcortical hyperdopaminergia (Howes et al).
evaluation 1- evidence for dopamine ( neural correlates : biological explanation of SZ)
-strength
-support for the idea that dopamine (DA) is involved in SZ
-amphetamines increase DA and worsen symptoms in people with schizophrenia and induce symptoms in people without (Curran). -antipsychotic drugs reduce DA activity and also reduce the intensity of symptoms (Tauscher).
-some candidate genes act on the production of DA or DA receptors.
-This strongly suggests that dopamine is involved in the symptoms of schizophrenia.
evaluation 2- glutamate ( neural correlates : biological explanation of SZ)
-limitation
-there’s evidence for a central role of glutamate.
-Post-mortem and live scanning studies have consistently found raised levels of the neurotransmitter glutamate in several brain regions of people with SZ (McCutcheon).
-also, several candidate genes for SZ are believed to be involved in glutamate production or processing.
-This means that an equally strong case can be made for a role for other neurotransmitters.
what are the 2 psychological explanations for SZ
-family dysfunction
-cognitive explanations
what is meant by family dysfunction
-refers to processes within a family such as poor family communication, cold parenting and high levels of expressed emotion
-might be the risk factors for both development of schizophrenia and maintenance of it
the schizophrenogenic mother- family dysfunction
-Fromm-Reichmann proposed a psychodynamic explanation for schizophrenia based on the accounts she heard from her patients about their childhoods.
-she noted that many of her patients spoke of a schizophrenogenic mother.
-‘Schizophrenogenic’ literally means ‘schizophrenia-causing’
-schizophrenogenic mother is cold, rejecting and controlling, and tends to create a family climate characterised by tension and secrecy.
-This leads to distrust that later develops into paranoid delusions and ultimately schizophrenia
double bind theory- family dysfunction
-Bateson et al agreed emphasised the role of communication style within a family.
-The developing child regularly finds themselves trapped in situations where they fear doing the wrong thing, but receive mixed messages about what this is, and feel unable to comment on the unfairness of this situation or seek clarification.
-When they ‘get it wrong’ the child is punished by withdrawal of love.
-This leaves them with an understanding of the world as confusing and dangerous, and this is reflected in symptoms like disorganised thinking and paranoid delusions.
expressed emotion- family dysfunction
-Expressed emotion (EE) is the level of negative emotion, expressed towards a person with schizophrenia by their carers who are often family members.
-EE contains several elements:
* Verbal criticism of the person, occasionally accompanied by violence.
* Hostility towards the person, including anger and rejection.
* Emotional overinvolvement in the life of the person, including needless self-sacrifice.
-These high levels of expressed emotion are a serious source of stress for them.
-This is primarily an explanation for relapse in people with schizophrenia.
-it has been suggested that it may be a source of stress that can trigger the onset of schizophrenia in a person who is already vulnerable due to their genetic make-up
evaluation 1- research support ( family dysfunction: psychological explanations for SZ)
-strength
-evidence linking family dysfunction to schizophrenia.
-Indicators of family dysfunction include insecure attachment and exposure to childhood trauma, especially abuse.
-Read et al = adults with schizophrenia are disproportionately likely to have insecure attachment
-Read et al. also reported that 69% of women and 59% of men with schizophrenia have a history of physical and/or sexual abuse.
-In the Morkved et al study most adults with schizophrenia reported at least one childhood trauma, mostly abuse.
-This strongly suggests that family dysfunction makes people more vulnerable to schizophrenia.
evaluation 2-explanations lack support ( family dysfunction: psychological explanations for SZ)
-limitation
-poor evidence base for any of the explanations.
-there is almost none to support the importance of traditional family-based theories such as the schizophrenogenic mother and double bind.
-Both these theories are based on clinical observation of people with schizophrenia and not systematic evidence.
-This means that family explanations have not been able to account for the link between childhood trauma and schizophrenia.
what is meant by cognitive explanations
explanations that focus on mental processes such as thinking,language and attention
dysfunctional thinking- cognitive explanations
-Schizophrenia is associated with several types of dysfunctional thought processing, and these can provide possible explanations for schizophrenia as a whole.
-Schizophrenia is characterised by disruption to normal thought processing.
-Reduced thought processing in the ventral striatum is associated with negative symptoms, whilst reduced processing of information in the temporal and cingulate gyri is associated with hallucinations
-This suggests that cognition is likely to be impaired
meta-representation dysfunction - cognitive explanations
-frith identified two kinds of dysfunctional thought processes.
-The first is metarepresentation, the cognitive ability to reflect on thoughts and behaviour.
-allows us insight into our own intentions,goals and interpret the actions of others.
-Dysfunction in metarepresentation would disrupt our ability to recognise our own actions and thoughts as being carried out by ourselves
-This would explain hallucinations of hearing voices and delusions