schizophrenia Flashcards
Define “schizophrenia”
a severe mental disorder where contact with reality and insights are impaired , an example of psychosis
- affects men more than woman
- severely impacts everyday life , those w schizophrenia usually end up homeless or in a hospital
Outline the two classification systems for mental disorders (schizophrenia )
Diagnostic and statistical manual ed5
(DSM-5)
- American Psychiatrics association
- more specific diagnostic criteria : requires more delusion , hallucinations and disorganised speech & catononic behaviour
International classification of disease
(ICD-10)
-World Health Organisations (WHO)
- broader approach to diagnosis : require paranoid delusions usually accompanied by hallucinations
Outline the main differences between the two classification systems for mental illnesses , in schizophrenia
Produced by different organisations
DSM-5 : American psychiatries association
ICD-10 : world health organisation
Type of symptom that must be present
DSM-5 : positive symptom present
ICD-10: 2 or more negative symptom present
Subtypes of schizophrenia
DSM-5: new model does not make these distinctions
ICD-10: makes these distinctions
why has the subtypes of schizophrenia been dropped from bot ICM and
tended to be inconsistent
e.g : someone with diagnosis of paranoid schizophrenia would not necessary show the same symptoms a few years later
What are positive symptoms
atypical symptoms experienced in addition to normal experiences
- enhance typical experience of sufferers
e.g hallucinations and delusions
What are negative symptoms
atypical experiences that represent the loss of a usual experience
e.g
speech poverty
avolition (lack of motivation)
Outline positive symptoms of schizophrenia
Hallucinations :
- distorted perception of real stimuli
OR
-perception of stimuli which have no basis in reality
-auditory hallucinations : thought to be caused by excess dopamine in Broca area
e.g : distorted facial expressions , seeing people/animal that are Not there , voices
Delusions
- set of beliefs with no basis in reality
e.g sufferer may be paranoid that they are being stalked by the royal family
-many different delusions :
e.g : delusional jealousy , somatic delusional disorders
Outline negative symptoms of schizophrenia
speech poverty
-abnormally low level of frequency and quality of speech
e.g delay in persons verbal responses during conversation
(however speech disorganisation classified at P symptom in DSM)
Avolition
-inability to cope with the normal pressures and motivation levels associated with everyday living and dayto-day tasks.
-difficult to carry out goal-driven activities
e.g : actions performed in order to carry out a result
Define Co-morbidity
the occurance of two disorders or conditions together
e.g a person has both schizophrenia and a personality disorder
- two conditions are usually diagnosed together , calls into question the validity of classifying two disorders separately
Define Co-morbidity
the occurance of two disorders or conditions together
e.g a person has both schizophrenia and a personality disorder
- two conditions are usually diagnosed together , calls into question the validity of classifying two disorders separately
eval points of diagnosis & classifications of schizophrenia
LIMITATIONS
- co-morbidity with other conditions - buckley et al
-cultural bias
-gender bias - cotton et al
-low validity - criterion validity - chenieux
Evaluate limitation of the diagnosis and classifications of schizophrenia (coo-morbidity)
high co-morbidity between schizophrenia and other conditions
- Buckley et al 2009 found that schizophrenia was often diagnosed with other MH conditions e.g post traumatic stress disorder
- researchers found : 29% of SZ patients suffered from ptsd and 50% suffered from depression
-esp in case of depression suggests that if SZ is so frequently diagnosed w/ other psychiatric disorders then, these disorders may actually be the same thing , so more accurate and valid explanation will be to combine these 2 explanations
-issues of validity in diagnosis of SZ & attempting to differentiate its symptoms from that of other diseases
Evaluate limitation of the diagnosis and classifications of schizophrenia (cultural bias)
cultural bias
- some symptoms of sz , such as hearing voices , may be deemed as a positive sign in certain cultures
-e.g in Haiti people believe hearing voices is communications from ancestors
-british people of african-carb origin are up to nine times likely as likely to recieve a diagnosis as white british people
(due to more openess about admitting sz symptoms)
also : diagnosis of clients by psychiatrics from diff cultural bg : overiinterpretation of symp
-britis african-carib can be discriminated against by a culturally biased diagnostic system
CP can be a genetic vunerability
Evaluate limitation of the diagnosis and classifications of schizophrenia (gender bias)
gender bias in diagnosis
-since 1980s there has been a rapid increase in diagnosis of SZ in men
-e.g cotton et al suggests that because there are no differences in genetic susceptibility for men and women in terms of SZ, then gender bias must be to blame
- dispositional traits of woman e.g : being able to work even when in pain : masks symptoms of SZ or distorts severity : not serious enough to call diagnosis
-current system of diagnosis for SZ does does not account for gender biases and differences : inaccurate diagnosis
Evaluate limitation of the diagnosis and classifications of schizophrenia (low validity)
low validity
-assessing validity of psychiatric diagnosis is criterion validity
- cheniaux had 2 psychiatrics independently assess same 100 clients using ICD-10 and DSM-IV and found 68 were diagnosed with SZ under ICD system and 39 under DSM
- SZ can be over/under diagnosed according to diagnostic system : criterion validity is low
CP: contradicting study : excellent agreement betweeen clinicians when both using DSM - CRITERION VALIDITY IS high when diagnosed under a single diagnostic system
Outline the genetic basis of SZ
Family studies
- evidence that sz runs in families ; appear to have a genetic basis : evidence found by Gottesman 1991
- someone w aunt : 2% of developing
- rising to 9% if sibling and 48% if MZ twin
HOWEVER: families also share the same environment : there are no 100% concordance rate
Candidate genes
- sz is polygenic : many diff candidate genes involved
-most likely to be genes coding for dopamine (DH)
- sz is aetiologically hetereogenous : diff combination of genes are implicated in disorder
mutations
-mutation in parental DNA due to radiation , poison or viral infection
State the Biological explanations of Schizophrenia
- Genetic basis
- The dopamine hypothesis
- Neural correlates
Outline research evidence for genetic explanation for SZ (family studies)
Gottesman 1991
- large scale family study
found : + correlation between increasing genetic similarity of family members and their increased chances of developing SZ
- concordance rates
MZ twins : 48%
DZ twins : 17%
parents : 6%
(explain mz and dz difference)
HOWEVEVER: family share same environment e.g schizophregenic mother etc (psychological explanations)
Outline research evidence for genetic explanation for SZ (candidate genes)
Ripke et al 2014
-combined all previous data from genome wide studies of SZ (looking at the whole genome)
-over 30k cases of swedish nationals with SZ was compared to a control group of over 100k (w/o sz)
- found 108 separate genetic variations associated with slightly higher risk of sz
Outline research evidence for genetic explanation for SZ (mutations)
- evidence for positive correlation between paternal age and increased of SZ
Brown et al 2002
-0.7% with fathers under 25
-2% with fathers over 50
SZ is likely to have a strong heritabilitycoefficient and biological basis
(can be used as eval for suggesting bio&genetic basis of sz)
Outline neural correlates explanation of SZ : original dopamine hypothesis
ORIGINAL
- hyperdopaminergia
-positive symptomps
- based on the discovery that drugs used to treat sz : antipsychotic drugs : block receptors that bind to dopamine : cause similar symptoms to those that have Parkinson’s disease
- Parkinson’s disease have a low level of dopamine
- therefore SZ may be the result of HIGH DA in subcortial areas of brain
- e.g excess of DA receptors (D2) in pathway from subcortex to broca area may explain certain symp of sz : speech poverty : or auditory hallucinations (overactivity of neurotransmission)
Outline neural correlates explanation of SZ : updated dopamine hypothesis
UPDATED
Davis et al
-INCLUDES cortical hypodopaminergia
- negative symptoms e.g : speech poverty and avolution ( in prefrontal cortex) : because prefrontal cortex is involved in logical thinking : abnormally low DA impairs this
- has been suggested : cortical hypodopaminergia leads to subcortical hypodopaminergia : both H and L levels of DA involved in updated version
-recently : both psychological and physical make people more sensitive to cortical hypodopaminergia and hence subcortrical hyperdop
What is the main difference between the old and new dopamine hypothesis
- old version only considers hyperdopaminergia whereas new considers cortical hypodopaminergia in addition to subcortical hyperdopaminergia
- old version considers only positive symtomps new version considers negative and positive (mainly negative)
eval points for biological approach to sz
genetic
STRENGTHS
- research support : adoption studies : Tienari et al
-application to real world:
WEAKNESS
-environmental factors
neural :DH
STRENGTH
-evidence to suggest that dopamine is involved in schizophrenia
WEAKNESS
-glutamate
Evaluate strengths of genetic explanation for SZ
there is research evidence to suggest a + correlation between increased genetic similarity and risk of SZ
- Tienari et al : biological children of parents with sz are at heightened risk even when adopted by an adoptive family
- people more vunerable to sz : depending on genetic makeup
CP : tienari sample consisted of only finnish participants : cultural bias : small population
real world applications
-genetic counselling
-can identify parents that are carriers of SZ candidate gene : child w/ sz : costs
-however environmental factors
Outline a limitations of the genetic approach to SZ
There are environmental factors that can also influence sz (etc reductionist : upbringing etc)
- can include both biological and psychiological factors
biological : birth complications and smoking THC-rich cannabis in teenage years (researchers have identified)
psychological :
-childhood trauma: more vunerable to adult mental health problems - research evidence found for sz
-67% of sz patients and related psychotic disorders reported atleast one childhood traumas compared to 38% of matched pair non SZ
Evaluate a strength of the dopamine hypothesis
evidence to suggest dopamine is involved in SZ
-e.g amphetamines
-AGONIST
increase DA
- worsen symptoms in people w sz
- induce symptoms in those w/o
- psychotic drugs :
-ANTAGONIST
reduce DA activity
reduce intensity of symptomps - candidate genes for sz are involved in production of DA symptomps
Evaluate limitation of dopamine hypothesis
evidence for central role of glutamate
- post mortem and live scanning studies : consistently found raised levels of neurotransmitter glutamate in several brain regions of sz ppl (McCutcheon et al)
- several candidate genes for sz are believed to be involved in glutamate production/processing
-over-reliance on dopamine : other neurotransmitters may have affect
