Psychology A2 - Schizophrenia
Classification & Diagnosis. Explanations. Therapies & Treatments
- Created by: Emily
- Created on: 11-12-11 15:06
Overview of Schizophrenia - Classification and Dia
- Nature of Schizophrenia
Profound disruption of cognition and emotion
Affects language, perception , affect and sense of self
Association with violence is largely a media invention
Around 8% of patients diagnosed with schizophrenia commit a serious act of violence but this figure is less than for other mental disorders.
- Diagnostic criteria
Positive symptoms - Excess of distortion of normal symptoms e.g. Delusions, Experiences of control, hallucinations, disorderded thinking.
A01 - continued
Negative symptoms - Diminution or loss of normal functions e.g. Affective flattening, Alogia, avolition
Diagnosis of schizophrenia - (a) Two or more symptoms. (b) Social/occupational dysfunction. (c) Duration - at least 6 months (d) Exclusion of mood disorder - Depression, bipolar (e) Exclusion of organic causes - Brain turmour, drug use
Overview of Schizophrenia - Classification and Dia
- Validity
Concerns question about what schizophrenia really is
First rank symptoms distinguish schizphrenia from other disorders, but some of these are also found in other disorders such as DID
Little evidence of shared prognosis in schizophrenia, therefore low predicitive validity
- Reliability
Extent to which psychiatrists can agree on the same diagnosis
DSM 3 and later versions claim increased reliability of diagnosis
Whaley - found inter-rater reliabilitiy as low as 0.11
A02 - continued.
Klosterkotter - Positive symptoms more useful for diagnosis than negative symptoms
Mojtabi and Nicholson - low inter-reliability of bizarre Vs Non-bizarre symptoms
Problem highlighted in Rosenhan's study 'on being sane in insane places'
- Synoptic links
Reliability of diagnosis challenged by difference between US and UK diagnosis (Copelane)
Explanations of Schizophrenia - Biological explana
- Genetic Factors
Schizophrenia more common among biological relatives of person with schizophrenia (Gottesman)
Twin studies - Joseph - pooled data shows concordance rate of MZ twins of 40% and DZ twins 7%
Use of 'blind' diagnosis produces lower concordance rate for MZ twins but still much higher than DZ
Adoption study by Tienari - if biological mother schizophrenic, 6.7% of adoptees also schizophrenia (2% of controls)
Explanations of Schizophrenia - Biological explana
- Commentary
Environment of MZ may be more similar than for DZ twins
Differences in concordance rates may reflect environment similarity rather than role of genetic factors
Adopted children from schizophrenic backgrounds may be adopted by particular type of adoptive parent, making conclusions difficult to draw.
Explanations of Schizophrenia - Biological explana
- Dopamine hypothesis
Neurons that transmit dopamine fire too easily or too often, leading to symptoms of schizophrenia
Schizophrenics - abnormally high levels of D2 receptors
Evidence from large doses of amphetamines (Dopamine agonist) causes hallucinations and delusions
Antipsychotic drugs - block and eliminate symptoms
Parkinsons's disease - treatment with L-dopa raises dopamine levels and can therefore also trigger schizophrenic symptoms
A01 - continued
Explanations of Schizophrenia - Biological explana
- Commentary
Drugs can increase schizophrenia symptoms as neurons try to compensate - Haracz found elavated dopamine levels in post-mortems of schizophrenics who had taken medication
Neuroimaging studies failed to provide convincing evidence for altered dopamine activity in schizophrenics.
Explanations of Schizophrenia - Biological explana
- Enlarged Ventricles
Ventricles of person with schizophrenia 15% bigger than non-schizophrenics
Display negative rather than positive symptoms
May be result of poor brain development or tissue damage
Explanations of Schizophrenia - Biological explana
- Commentary
Meta-anaylsis found substantial overlap in ventricle size among schizophrenic and control populations
Enlarged ventricles may be due to effects of antipsychotic medication
- Synoptic links
Many studies have to include schizophrenia spectrum disorders to show genetic influences
Evolutionary perspective - Schziophrenia may have adaoptive advantages (Group splitting hypothesis)
Explanations of Schizophrenia - Psychological expl
- Psychological therapies
- Psychodynamic view of schizophrenia
Result of regression to pre-ego state and attempts to re-estabilish ego control
Some schizophrenic symptoms reflect infantile state, other symptoms are an attempt to re-establish control
Further features of disorder appear as individuals attempt to understand their experiences
They may reject feedback from others and develop delusional beliefs
Explanations of Schizophrenia - Psychological expl
- Commentary
Very little evidence to support psychodynamic view of schizophrenia
Behaviour of parents assumed to be key influence in development of schizophrenia but may be consequence rather than cause
Cognitive explanation supported by neurophysiologic evidence (Meyer - lindenberg)
Explanations of Schizophrenia - Psychological expl
- Socio-cultural factors
Prior to schizophrenic episode, patients report twice as many stressful life events
Link demonstrated inboth retrospective (brown and birley) and prospective (Hirsch) studies
Double - bind theory - contradictory messages from parents prevent coherent construction of reality, leads to schizophrenic symptoms
Expressed emotion - family communication style involving criticism, hositility and emotional over-involvement
Leads to stress beyond impaired coping mechancisms and so schizophrenia
Labelling theory - symptoms of schizophrenia seen as deviant from rules ascribed to normal experience. Diagnostic label leads to self-fulfilling prophecy
Explanations of Schizophrenia - Psychological expl
- Commentary
Some evidence challenges link between life events and schizophrenia. Evidence for link is only correlational, not causal
Importance of family relationships in development of schizophrenia shown in adoption study by Tienari
Double-bing theory supported by Berger - Schizophrenics recalled more double-bind statements from mothers
Expressed emotion - has led to effective therapy for relatives
Scheff - 13 of 18 studies consistent with predicitions of labelling theory
- Synoptic links
Expressed emotion effects much less common in collectivist cultures.
Therapies of Schizophrenia - Biological therapies
- Antipsychotic medication
Conventional antipsychotics reduce effects of dopamine and so reduce symptoms of schizophrenia
Bind to D2 dopamine receptors but do not stimulate them
Atypical antipsychotics only temporarily occupy D2 receptors then dissociate to allow normal dopamine transmission
Leads to lower levels of side effects such as tardive dyskinesia
Therapies of Schizophrenia - Biological therapies
- Commentary
Davis - higher relapse rate in patients whose drug replaced with placebo than those who remained on drug
Antipsychotic medication more effective for those living with hostility and criticism
Conventional antipsychotics - 30% develop tardive dyskinesia
Being prescribed medication creates motivational deficits which prevents positive action against illness
Meta-analysis (leucht) - superiority of atypical over conventional antipsychotics only moderate
Atypical antipsychotics - only marginal support for effectiveness with negative symptoms
A02 - continued
Lower rates of tardive dyskinesia with atypical antipsychotics supported by Jeste
Patients more likely to continue with medication if fewer side effects
Therapies of Schizophrenia - Biological therapies
- ECT
First studies of ECT as treatment for schizophrenia were disappointing - Karagulla - with recovery lower than control group
Tharyan and Adams - review of 26 studies found 'real' ECT more effective than 'sham' ECT
Combination of medication and ECT effective rapid reduction of symptoms
Therapies of Schizophrenia - Biological therapies
- Commentary
Effectiveness of ECT is inconsistent. APA study found no difference between effects of ECT and Antipsychotic medication
Sarita - No difference in symptom reduction between ECT and simulated ECT
Because of risks of ECT (E.g. Memory dysfunction, brain damage) use has declined.
- Synoptic links
Ross and Read - Placebo studies not a fair test because proportion of relapses explained by withdrawal effects
Ethical issues - Human rights issues associated with use of antipsychotic medication (Tardive Dyskinesia)
Therapies of Schizophrenia - Psychological therapi
- CBT
Patients - Trace origins of symptoms to understand how they might have developed and evaluate content of delusions and hallucinations
Patients allowed to develop own alternative to maladaptive beliefs
Outcome studies show that patients receiving CBT experience fewer hallucinations and delusions than those receiving antipsychotic medication alone
Lower patient drop-out rates and greater patient satisfaction with CBT than antipsychotic medication
Therapies of Schizophrenia - Psychological therapi
- Commentary
Effectiveness - Meta analysis found significant decreases in positive symptoms after CBT treatment
Most CBT studies also involve antipsychotic medication, therefore difficult to assess effects of CBT alone
CBT works by generating less distressing explanations for psychotic experiences rather than trying to eliminate them.
Psychiatrists believe that older patients are less likely to benefit from CBT
Therapies of Schizophrenia - Psychological therapi
- Psychodynamic therapies
Psychoanalysis based on assumption that individuals unaware of influences of unconscious conflicts on their current psychological state
Therapist creates an alliance with patient by offering help with what patient perceives as the problem
All psychodynamic therapies build trust with patient by replacing hard parental conscious with one that is more supportive
As patient gets healthier they take a more active role
Therapies of Schizophrenia - Psychological therapi
- Commentary
Meta-anaylsis - Gottdiener - 66% of those receiving psychotherapy improved after treatment whilst 35% didn't
Some forms of psychodynamic therapy can even be harmful in treatment of schizophrenia
Research on effectiveness of psychodynamic therapy shows contradictory findings
Supportive psychotherapies appropriate when combined with antipsychotic medication
Psychodynamic therapy long and expensive, but may have benefits in that it might make patients more able to seek employment
A02 - continued
- Synoptic links
Methodological limitations of psychodynamic outcome stuies include lack of random allocation to therapy conditions
Ethical issues arise in placebo condition where patients are denied effective treatment
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