Psychology A2 - Schizophrenia

• 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.

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

• 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

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)

• 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)

• 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.

• 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

• 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.

• 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

• 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)

• 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

• 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)

• 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

• 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.

• 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

• 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

Lower rates of tardive dyskinesia with atypical antipsychotics supported by Jeste

Patients more likely to continue with medication if fewer side effects

• 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

• 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)

• 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

• 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

• 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

• 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

• 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