schizophrenia Flashcards
1
Q
classification
A
DSM-5:
- 1 positive symptom must be present
ICD-10:
- 2/more negative symptoms are sufficient for diagnosis
2
Q
positive symptoms
A
addititional experiences beyond those of ordinary existence
- hallucinations - sensory experiences that have no basis in reality / distorted perceptions of real things
- delusions - beliefs that have no basis in reality
3
Q
negative symptoms
A
loss of usual abilities + experiences
- avolition - severe loss of motivation to carry out everyday tasks, e.g. work, hobbies, personal care; results in lower activity levels
- speech poverty - reduction in amount + quality of speech; may include delay in verbal responses during conversation
4
Q
diagnosis & classification
AO3
A
✘ low reliability
- Cheniaux et al got 2 psychiatrists to independently diagnose 100 pxs using both DMA + ICD criteria
- inter-rater reliability proved to be poor
- shows inconsistency between mental health professionals + the different classification systems
✘ low validity
- Cheniaux’s study shows that schizophrenia is much more likely to be diagnosed using ICD rather than DSM
- suggests that the condition is either overdiagnosed in ICD or underdiadnosed in DSM
✘ co-morbidity
- which confuses diagnosis and treatment
- symptom overlap questions the validity of the classification
- comorbidity questions validity of diagnosis
✘ lacks predictive validity
- Szs rarely share same symptoms so rarely share same outcomes
- affects each person differently
- difficult to predict outcome of each person
✘ gender bias
- longenecker found that men were more likely to be diagnosed than women
- Could be men are more genetically vulnerable
- Women - better functioning than men
- harder to diagnose in women - high functioning masks symptoms of Sz
- Loring and Powell (1988) - patient more likely to be diagnosed with Sz by male clinician when described as ‘male’ - not evident in females. Gender bias - based on gender of patient and clinician.
✘ culture bias
- rastafarians smoke cannabis - side effect - hallucinations + paranoia
- people of afro-carribbean origin 7 times more likely to be diagnosed when living in Uk
5
Q
biological explanation
GENETIC BASIS
A
- strong relationship between genetic similarity of family members + likelihood of both developing schizophrenia
- family studies have found that MZ twins have higher shared risk of schizophrenia that DZ twins who have higher shared risk than siblings
- candidate genes have been identified which create a vulnerability to schizophrenia
- a no. of these genes have been discovered, making schizophrenia polygenic
- each of these only confer a small increased risk
- there are numerous combinations that can lead to schizophrenia, making it aetiologically heterogeneous
6
Q
genetic basis
AO3
A
✔ research support
- adoption studies have shown that children of people w Sz are at a heightened risk of developing Sz, even when adopted into families w/o Sz
- strongly suggests a genetic vulnerability to Sz
✘ too many genes involved
- difficult to pin them all down
- unlikely to be useful as it provides v little predictive value
✘ ignores environmental influences
- shared risk of Sz for MZ is still less than 50%
- there are evidence of environmental factors, e.g. family functioning during childhood, that play a role
- suggests Sz is a result of a combination of both biological + psychological influences
- best explained by an interactionist approach
7
Q
biological explanation
DOPAMINE HYPOTHESIS
A
dopamine is featured in the functioning of brain systems related to symptoms of Sz
hyperdopaminergia
- OG version of hypothesis
- focused on high levels of DA activity in subcortex
- e.g. excess of DA receptors in Broca’s area which is responsible for speech production
- associated w hallucinations + speech poverty
hypodopaminergia
- more recent version of hypothesis
- focused on low levels of DA in pre-frontal cortex
- responsible for thinking + decision-making
8
Q
dopamine hypothesis
AO3
A
✘ mixed evidence
- DA agonists (e.g. amphetamines) that increase levels of DA can induce schizophrenic symptoms in people w/o Sz
- antipsychotic drugs that reduce DA activity, however, can be effective in reducing symptoms
- radioactive labelling studies found that chemicals needed to produce DA are taken up faster in brains of people w Sz, suggesting they produce more DA
✘ incomplete explanation
- some of the candidate genes identified also code for other NTs
- suggests there are other important NTs involved in Sz
- e.g. glutamate
9
Q
biological explanation
NEURAL CORRELATES
A
measurements of structure + function of the brain that correlate w symptoms of Sz
- e.g. ventral striatum is involved in motivation
- low activity levels result in avolition
- pxs experiencing auditory hallucinations had low activity levels in superior temporal gyrus
10
Q
neural correlates
AO3
A
✘ cause + effect
- research only demonstrates a correlation, not cause + effect
- could just be that the negative symptoms themselves means less info is passed through the ventral striatum, resulting in low activity
11
Q
biological therapies
TYPICAL ANTIPSYCHOTICS
A
work by acting as DA antagonists by blocking DA receptors in the synapses of the bran, reducing the action of DA
- e.g. chlorpromazine
- effect histamine receptors
- provide sedation effect
- used to calm anxious pxs
12
Q
biological therapies
ATYPICAL ANTIPSYCHOTICS
A
- aim to improve effectiveness of drugs in suppressing schizophrenia
- target no. of NTs
e.g. clozapine
- binds to DA, serotonin + glutamate receptors
- more effective than TAs
- reduce anxiety + depression, improve cognitive functioning
e.g. risperidone
- developed as clozapine was involved in px deaths
- binds more strongly to receptors
- so more effective in smaller doses
- fewer side effects
13
Q
biological therapies
AO3
A
✔ research support
- Thornley et al found that chrorpromazine was associated w better functioning + reduced symptom severity compared w placebos
- further research found that clozapine is more effective than TAs
✘ side effects
- TAs side effects incl: dizziness, sleepiness, agitation, weight gain
- may cause pxs to discontinue use so limits effectiveness
- most serious side effect = NMS
- caused by blocking DA receptors in hypothalamus - can be fatal
✘ individual differences
- drugs don’t work in the same way for everyone
- small genetic variations between individuals have a significant impact on the effectiveness of a drug
- drugs need to be more tailored to individual genetic profiles
14
Q
psychological explanation
FAMILY DYSFUNCTION
A
schizophrenogenic mothers
- psychodynamic explanation
- cold, rejecting + controlling
- create family climate of tension + secrecy
- leads to distrust + paranoid delusions
- leads to schizophrenia
double-bind theory
- conflicting family communications
- child in situations where they fear doing the wrong thing but uncertain what is wrong
- when they do get it wrong, they are ounished by withdrawal of love
- leads to disorganised thinking + delusions
expressed emotion
- level of negative emotion expressed towards patient
- includes: verbal criticism, hostility + emotional over-involvement in their life
- high levels can cause stress in px + can lead to relapse
15
Q
family dysfunction
AO3
A
✔
✔
✘
✘
