Schizophrenia Flashcards
(27 cards)
reliability and validity in diagnosis and classification
the nature of schizophrenia
a severe mental disorder in which though and emotions are so impaired that contact is lost with external reality
diagnosis made on basis of criteria on DSM-V - requires two or more active symptoms for at least one month
positive symptoms reflect an excess or distortion of normal functions
include hallucinations, delusions, disorganised speech and grossly disorganised or catatonic behaviour
negative symptoms reflect a reduction or loss of normal functions
include speech poverty (alogia), avolition, affective flattening and anhedonia
reliability
diagnostic reliability means diagnosis must be repeatable (test-retest reliability)
different clinicians should reach the same diagnosis
cultural differences in diagnosis (Copeland), experience of voices (Luhrmann et al.) and ethnic differences (Barnes)
reliability evaluation
lack of inter-rater reliability - as low as 0.11 (Whaley and misdiagnosis of ‘pseudo patients’ (Rosenhan)
validity
the extent that a diagnosis represents something that is real and distinct from other disorders
gender bias in diagnosis - tendency to pathologies of one gender rather than another
Goldstein and Kreisman - schizophrenic sons more readily seen as ‘ill’ than schizophrenic daughters, accounting for earlier diagnosis of schizophrenia
symptom overlap - different disorders can share symptoms, making diagnosis difficult
co-morbidity - two or more conditions may co-exist, e.g. ‘schizo-OCD’ (Swets et al)
validity evaluation
research support for gender bias in diagnosis - males more likely to be diagnosed with schizophrenia (Loring and Powell)
the consequences of co-morbidity - co-morbid non-psychiatric diagnoses may compromise treatment and prognosis (Weber et al.)
differences in prognosis - patients rarely share the same symptoms nor the same prognosis
genetic factors evaluation
MZ twins encounter more similar environments - explains higher concordance rates
adoptees may be selectively placed - suggests that adoptive parents of children at risk of schizophrenia not typical
genetic factors
genetic explanations emphasise the importance of inherited factors
family studies - schizophrenia more common among biological relatives of a person with the disorder
twin studies - show higher concordance rate for MZ twins than for DZ twins
adoption studies - Tienari et al. found greater link with biological parents than adoptive parents
neural correlates: the dopamine hypothesis
dopamine hypothesis claims excess of dopamine causes positive symptoms of schizophrenia
drugs that increase dopamine (e.g. amphetamines) produce schizophrenic symptoms and drugs that decrease dopamine (antipsychotics) reduce symptoms
revised dopamine hypothesis - include dopamine under activity in PFC
neural correlates: the dopamine hypothesis evaluation
evidence from treatment - evidence from success of antipsychotic treatments that reduce dopamine activity in the brain
challenges to the dopamine hypothesis - antipsychotics don’t decrease symptoms in everyone and some schizophrenic have normal dopamine levels
neural correlates: specific brain areas; grey and white matter
cognitive symptoms due to impairment in PFC and its connections with other brain regions (e.g. the hippocampus)
individuals with schizophrenia show grey matter deficits and enlarged brain ventricles (Cannon et al., 2014)
reduced myelination of white matter pathways in schizophrenic patients (Du et al., 2013)
neural correlates: specific brain areas; grey and white matter evaluation
support for influence of grey matter deficits - from meta-analysis of 19 studies (Vita et al., 2012)
implications for treatment - early detection of neural correlates allows treatment to prevent full development of psychosis (e.g. NAPLS study)
family dysfunction
double bind theory - conflicting messages within the family prevents coherent construction of reality, giving rise to schizophrenic symptoms
expressed emotions - family communication style likely to influence relapse rates suggests lower tolerance for intense environmental stimuli
family dysfunction evaluation
family relationships - disturbed adoptive families more likely to trigger schizophrenia in children with genetic vulnerability (Tienari et al)
double bind theory - schizophrenics reported higher recall of double bind statements than non-schizophrenics (Berger), although other studies less conclusive
individual differences in vulnerability to EE - not all schizophrenics respond negatively to high EE. how patients appraise behaviour important
cognitive explanations
cognitive explanations of delusions - egocentric bias leads person to relate irrelevant events to themselves and arrive at false conclusions
cognitive explanations of hallucinations - hyper vigilance leads to greater expectation for stimuli; person likely to attribute these external sources
cognitive explanations evaluation
supporting evidence for the cognitive model of schizophrenia - Sarin and Wallin found evidence that positive symptoms arise from faulty processing
support from the success of cognitive therapies - CBT more effective at reducing symptom severity than antipsychotics
an integrated model of schizophrenia - early vulnerabilities sensitise dopamine system more dopamine released, biased processing results in paranoia/hallucinations
antipsychotics
work by reducing dopaminergic transmission in areas of brain associated with schizophrenia
typical antipsychotics - use to combat positive symptoms. atypical antipsychotics also claimed to treat negative symptoms
typical antipsychotics are dopamine antagonists - block action of dopamine and so reduce hallucinations and delusions
between 60% and 75% of D2 receptors must be blocked for drugs to be effective
atypical antipsychotics show rapid dissociation from D2 receptors also strong affinity for serotonin receptors
also acts as serotonin agonists, leading to increased dopamine release in prefrontal cortex to reduce negative symptoms and cognitive impairment
antipsychotics evaluation
antipsychotics versus placebo - antipsychotics more effective than placebo at reducing relapse rates (Leucht et al)
extrapyramidal side effects - typical antipsychotics impact on areas of the brain that control motor activity. include parkinsonian symptoms and tar dive dyskinesia
ethical problems with typical anti-psychotics - cost-benefit analysis may be negative also human rights abuse because of side effects
advantages of atypical over typical antipsychotics - fewer side effects than typical antipsychotics so more likely to continue with medication
are atypical antipsychotics better than typical? Crossley et al. conclude no difference in efficacy but different side effects
motivational deficits - antipsychotic treatment reinforces ‘something wrong’ view and reduces motivation to look for other possible causes
cognitive behavioural therapy for psychosis (CBTp)
basic assumptions is that people have distorted beliefs which need to be changed through therapy
CBTp techniques - client encouraged to test validity of their faulty beliefs and set behavioural assignments to improve functioning
therapists help patients develop alternative explanations to replace maladaptive beliefs
how does it work? through: assessment; engagement; ABC model; normalisation; critical collaborative analysis; developing alternative explanations
CBTp evaluation
advantages of CBTp over standard care - consistent evidence that it reduces hospitalisation rates and symptom severity
effectiveness of CBTp is dependent on the stage of the disorder - more effective after stabilisation of symptoms with antipsychotic medication
lack of availability of CBTp - research (e.g. Haddock et al.) suggests only small proportion of people are offered CBTp
problems with meta-analysis of CBTp as a treatment of schizophrenia - they fail to control for study quality, leading to biased findings
the benefits of CBTp may have been overstated - as sole treatment may produce only a small beneficial effect (Jauhar et al)
family therapy
interventions aimed at the family of someone with schizophrenia
aims to reduce rates of EE within families as EE increases likelihood of relapse
Garety et al estimated relapse rate of 25% for family intervention, 50% for standard care alone
involves proving family members with information about schziophrenia, finding ways to support and resolve practical problems
how does it work? through: psychoeducation; forming an alliance with relatives; reducing emotional climate; enhancing relatives problem-solving skills; reducing expressions of anger and guilt; maintaining reasonable expectations; encouraging relative to set appropriate limits
key study Pharoah et al (2010)
procedure: 53 studies that had compared family intervention with standard care (antipsychotic medication alone)
findings: strongest effect was on increased compliance with medication. also reduced relapse and readmission rates, social functioning but mixed results on mental state changes
family therapy evaluation
why is family therapy effective? may be effective only because it improves compliance with antipsychotic medication
a methodological limitation: lack of blinding - not all studies in Pharoah et al meta analysis had used randomisation or blinding
economic benefits of family therapy - extra cost of family intervention is offset by reduction of costs of hospitalisation associated with relapse
impact on family members - Lobban et al analysed 50 studies and found 60% reported positive impact on relative
is family therapy worthwhile? Garety et al found it did not improve with relative proving a good standard of care
token economy
form of behavioural therapy used in the management of schizophrenia
uses tokens and exchange for rewards to increase target behaviours
Ayllon and Azrin increased desirable behaviours on ward of female schizophrenics
tokens are secondary reinforces exchanged for primary reinforcers
tokens acquire reinforcing abilities through association
generalised secondary reinforces more powerful
patients trade tokens - timing of reinforcement important
token economy evaluation
research support - 11 of 13 studies reported beneficial effects but some methodological difficulties (Dickerson et al)
difficulties assessing the success of a token economy - tend not to involve control group, making it difficult to assess effectiveness
less useful for patients living in the community - difficult to administrate
ethical concerns - including infringement of basic human rights
does it actually work? difficult to assess as few randomised trials and no longer front-line treatment in UK
