Schizophrenia Flashcards
What are the two classification systems of schizophrenia and how do they differ ?
ICD 10
DSM 5
DSM 5 says one positive symptom must be present
ICD 10 two or more negative symptoms must be present
What are negative symptoms of schizophrenia?
Loss of usual abilities and experiences
- Avolition = Severe loss of motivation
- Speech poverty = Reduction in the amount and quality of speech
eg DSM emphasises speech disorganasation and poverty
What are the positive symptoms?
Additional experiences beyond those of ordinary existence
- Hallucinations - sensory experiences that have no basis in reality or distorted perceptions of real things
eg seeing people that are not there - Delusions - beliefs that have no basis in reality
eg conspiracies
What are the issues with diagnosis?
- Reliability - the extent to which the diagnosis of schizophrenia is consistent
- Validity - the extent to which diagnosis measure what they set out to measure
- Co Morbidity - occurence of 2 illnesses together which confuses diagnosis and treatment
- Symptom overlap - 2 or more conditions share symptoms, questioning the validity
A03 EVALUATION - diagnosis and classification of schizophrenia
LIMITATION - Diagnosis has low reliability
- poor interater reliability eg 1 psychiatrist diagnoses 26 using DSM and 44 using ICD/// 2nd psychiatrists diagnosed 13 with DSM and 24 with ICD
LIMITATION - Co morbidity
- buckley found 1/2 of patients also have a diagnosis of depression (50%) or substance abuse (47%)
LIMITATION - gender bias
- women are able to escape diagnosis
LIMITATION - cultural bias
- abnormalities eg hearing voices
What is the biological explanation of SZ?
- SZ runs in families
—–> genetic similarity of of family members and likelihood of both developing schizophrenia
—–> MZ twins have 48% shared risks
—–> Schizophrenia is polygenetic = each individual gene confers a small increased risk of SZ
—–>Schizophrenia is aetiologically heterogenous = different combos can lead to SZ - Dopamine Hypothesis
—–> Dopamine is involved as it is featured in the functioning of brain symptoms
—–> Hyperdopaminergia : High DA activity in subcortex associated with hallucinations and poverty of speech (excess of dopamine receptors in brocas areas)
—–> Hypodopaminergia : Low DA activity in prefrontal cortex (thinking and decision making) - Neural correlates
—–> Measurements of the structure or function of the brain that correlate with (+/-ve) symptoms
—–> Ventral striatum involved in anticipation of reward (avolition)
—–> Juckel found a negative correlation between ventral striatum and negative symptoms
—–> Allen found that patients experiencing auditory hallucinations recorded lower activation levels in the superior temporal gyrus
A03 - biological explanation of SZ?
STRENGTH - Strong evidence for genetic vulnerability
- Adoption studies show children of SZ are still at heightened risk if adopted into families without
STRENGTH - role of mutation supports genetic explanation
- sz can take place in the absence of family history of disorder (mutation of paternal dna in sperm cells)
- increased risks between paternal age and sz (0.7% in dads under 25 and 2% in fathers over 50)
LIMITATION - clear that the environment is also involved
- probability of developing SZ even if identical twin has it is less that 50%
- evidence that ebvironmental factors can also play a role
- biological and physiological approaches
LIMITATION - mixed support for dopamine hypothesis
- dopamine antogonists that increase DA can induce sz symtoms in people without
- antipsychotics can lower dopamine can also reduce symptoms
- some of the candidate genes identiifed code for the production of neurotransmitters such as glutamate
- this suggests that DA cannot provide a complete explanation for SZ
What are the psychological explanations of SZ?
- Family dsyfunction
—> Reichmans psychodynamic explanations based on patients early experiences of schizophregenic mothers (mothers who cause schizophrenia - rejecting, controlling, create a family climate of tension and secrecy —> paranoid delusions)
—> Double bind theory = Bateson described how a child may be regularly trapped in situations where they get conflicting messages about what is wrong so they fear doing wrong. They cannot express their feelings.
= When they get it wrong the child is punished with withdrawal of love - learn the world is confusing which leads to delusions
—> Expressed emotion is the level of emotion expressed towards sz patients (verbal criticism, hostility, emotional over involevement) this leads to relapse
- Cognitive explanations
—> Dysfunctional thought processing = low levels of information processing in some areas of brain suggests cognition is impaired eg reduced processing in ventral striatum associated with (-ve symptoms)
—> Metarepresentation = the cognitive ability to reflect on thoughts and behaviour which distrupts our ability to recognise our own which leads to (+ve) symptoms
—> Dysfunction of central control leads to speech poverty = central control being the cognitive ability to suppress automatic responses while performing deliberate actions = people with sz experience derailment of thoughts and spoken sentences becuase each word troggers automatic responses they cannot suppress
A03 evaluation - psychological explanations of sz?
LIMITATION - Evidence for family relationships is poor
—> Although there is plenty of evidence supporting the idea that childhood family based stress can cause SZ there is no support on theories such as schizophregenic mother and double bind
—> These theories are based on clinical observation and infromal assessment of mothers peronsality but not systematic evidence
—> Family explanations have not been able to account for the link between childhood trauma and SZ
STRENGTH - Support for different information processing
- Stirling et Al compared 30 patients with SZ to 18 w/out (control) on cognitive tasks (stroop tests (colour different to word eg purple)
- Patients took longer to surpress impulse to read word and name ink instead
- Supports friths theory of central control dysfunction
- HOWEVER it is not clear whether these faulty cognitions are the proximal cause (cause of symptom) or distal cause (origins)
LIMITATION - Evidence for family relationships is retrospective
- Read at al reviewed 42 studies and concluded 69% of all female inpatients and 59% men with SZ had history of physical/sexual abuse in childhood
- Evidence is based on information about childhood experiences but the symptoms may have distorted the patients recall of their childhood experiences
LIMITATION - Biological factors overlooked
- Psychological explanations can be hard to reconcile with biological ones
- If the biological ones are valid how do they fit with psychological ones?
- Both psych and biological factors can separately produce seperate symptoms - are both outcomes sz
- View as diathesis stress model where diathesis be biological or psychological
BIOLOGICAL THERAPIES (drugs) - What is atypical antipsychotics?
—> Target dopamine and serotonin eg CLOZAPINE
—> The drugs are used to improve effevtiveness of drigs in surpressing psychoses of sz and reduce side effects
—> CLOZAPINE acts on dopamine, glutamate and serotonin to improve mood
—> Reduces depression, anxiety and improves cognitive functioning
—> 300-450 mg
—> RISPERIDONE binds to dopamine and serotonin
—> Developed because clozapine was involved in deaths of some patients from a blood condition
—> Risperidone binds more strongly so more effective in smaller doses and smaller side effects
—> Tablet, syrup or injection
—> 4-8mg max of 12 mg
BIOLOGICAL THERAPIES (drugs) - What is typical antipsychotics?
> > > > Dopamine antogonists
—> reduce action of dopamine by working as antagonists
—> block dopamine receptors in the synapses of the brain reducing action of dopamine
—> dopamine levels build up after taking CHLORPROMAZINE but then production is reduced, which normalises neurotransmission in key areas of the brain which reduces symptoms
—-> CHLORPROMAZINE has an effect on histamine receptors which leads to sedation effect
A03 EVAL BIOLOGICAL THERAPIES
STRENGTH - Antipsychotics are moderately effective
—> Thornley reviewed data from 13 trials and found CHLORPROMAZINE was associated with better functioning and reduced symptom severity compared with placebo
—> Support for atypical antipsychotics
—> Meltzer concluded clozapine is more effective then typical antipsychotics and that it is 30-50% more effective in treatment resistant cases
LIMITATION - Antipsychotics side effects
—>dizziness, agitation, sleepiness, weight gain and long term would lead to lip smacking due to dopamine super sensitivity
—> most serious side effect is NMS caused by blocking dopamine action in hypothalamus (disrupts regulation of several body systems)
—> can put people off
LIMITATION - Doubts about true effectiveness of antipsychotics
—> data have been published multiple times exaggerating the positive effects
—> most studies only review short term effects
—> antipsychotics have powerful calming effects but may not actually reduce psychosis
—> effectiveness may be overestimated by empirical reserach
What are the the Psychological therapies ?
CBT
> This is where they help patients identify irrational thoughts and try to change them
> Patients are helped to make sense of how theur delusions and hallucinations impact on feelings and behaviour
> Helps to reduce anxiety and helps patients belief are not based on reality
Family Therapy
> improve communcation and interaction
> reduce stress and ee to ensure no relapse
> Strategies used :
1. reduce stress of caring for a relative
2. Improve ability to anticipate and solve problems
3. Reduce guilt and anger
4. Improve beliefs and behaviour towards SZ
Token Economies
> Reward systems (operant conditioning) in order to carry out desirable behaviours
> Patients need to make bed or get dressed etc to get a token
> Reinforces behaviour and reduces effect of delayed rewards
> Tokens can be swapped for sweets, a walk outside etc
> They are SECONDARY REINFORCERS becuase they only have value due to learned assocation (classical conditioning) with innate primary reinforcers
A03 EVAL psychological therapies
LIMITATION - limited benefits
- Significant but small effect on positive/negative symtoms
- One of three studies of token economies thta used random allocation showed improvement
- Pahroah reviewed effectiveness of family studies and found moderate eveidence for reduction of readmissions and some improvement to quality of life but evidence was inconsistent
LIMITATION - they help but not cure
- CBT helps them make sense of symptoms
- Family therapy reduces stress
- token economies make the behaviuor more acceptable
LIMITATION - ethical issues
- Token economies arent used with severely ill patients as they are less likely to comply with desirable behaviours
- Severyly ill patients suffer discrimnation
- CBT can challenge paranoia but also interfere woth freedom of thought
LIMITATION - alterntaives under researched
- art theroay to help those iwth sz
- not well researched so not effective
- questions the validity
What is the interactionist approach?
- The diathesis stress model
- vulnerability and stress trigger needed to develop sz - Meehls model
- the schizogene is necessary but not sufficent for development of SZ
- the gene makes them vulnerable to effects of chronic stress - Modern understanding of diatehsis
- sz due to many genes that increase vulnerability
- diathesis could not just be genetic but also things like pschologivcal trauma affecting brain development eg child abuse - Modern understanding of stress
- anything that risks triggering SZ
- eg cannabis can increase the risk upto 7 times as it interferes with dopamine system
