Classification and Diagnosis
- Profound disruption of cognition and emotion - affects language, perception and sense of self.
- Diagnosis os SZ - under DSM - IVR: requires at least 1 month duration of 2 or more positive symptoms
- positive symptoms = excess or distortion of normal symptoms, e.g. delusions (bizarre beliefs), experiences of control (by alien force), hallucinations (unreal perceptions), disordered thinking (thought insertions)
- negative symptoms = diminution or loss of normal functions e.g. affective flattering ( reduction in emption expression) Alogia (poverty of speech) avolition (lack of goal - directed behaviour.
Classification and Diagnosis
- Inter - rater reliability - DSM III and later versions claim increased reliability of diagnosis.
- test - retest reliability - screening tests such as RBANS show high test - retest reliability (Wilks et al, 2003)
- Inter - rater reiability - despite claims for increased reliability, there is still little evidence that DSM is routinly used with high reliability by mental health clinicians.
- demonstration on unreliability of diagnosis = (Rosenhan, 1973)
- unreliable symptoms - diagnosis based on bizarre delusions not a reliable method of distnguishing between schizophrenic and non patients. (Mojtabi and Nicholson, 1995)
- Test - retest reliability (prescott et al, 1986) performance on measures of schizophrenia stable over 6 month period.
- Comparing DSM to ICD - SZ = more frequently diagnosed according to ICD -10 than DSM IV criteria (Cheniaux et al, 2009)
- reliability of diagnosis challenged by difference between US and UK diagnoses (Copeland, 1971)
Classification and Diagnosis
- Psychiatric comorbidities are common among patients with SZ and create difficulties in diagnosis of SZ.
- (Klosterkotter et al, 1994) - positive symptoms more useful for diagnosis than negative.
- Prognosis - people diagnosis as SZ rarely share the same symptoms, nor the same outcomes
- Comorbidity and medical complications - (Webber et al, 2009) found evidence of many comorbid non - psychiatric diagnoses among patients with SZ, which affects prognosis.
- Comorbidity and suicide risk - persons with SZ at risk for suicide, with comorbid depression the major cause for suicidal behaviour (Kessler et al, 1994).
- Ethnicity and msdiagnosis - rates of SZ among African - Caribbeans muh higher than white populations (Harrison et al, 1997) which in part may be a product of misdiagnosis.
- Symptoms - SZ symptoms also found in many other disorders, incl. depression and DID (Elason and Ross, 1995) .
- First studies of ECT as treatment for SZ were disappointing (Karagulla, 1950), with recovery lower than control group.
- Combination of medication and ECT effective for rapid reduction of symptoms.
- Effectiveness of ECT is inconsistent. APA study found no difference between effects of ECT and antipsychotic medication
- (Sarita et al, 1998) - no diference in symptom reduction between ECT and simukated ECT.
- (Tharyan and Adams, 2005) - review of 26 studies, found 'real' ECT more effective than 'sham' ECT.
- Conventional antipsychotics reduce effects of dopaine, and so reduce symptoms of SZ.
- 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.
Anti psychotic medication evaluation:
- (Davis et al, 1980) - higher relapse rate in patients whose drug replaces 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 prevent positive action against illness.
- Meta - analysis (Leucht et al, 1999) - 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, suppported by (Jeste et al, 1999).
- patients more likely to continue with medication if fewer side effects.
- (Ross and Read, 2004) placebo study not a fair test because proportion of relapses explained by withdrawal effects
- Ethical issues - human rights issue associated with use of antipsychotic medication (TD)
- Patients: 1) trace origins of symptoms to understand how they might have developed and 2) evaluate content of delusions / hallucinations.
- Patients allowed to develop own alternatives to maladaptive beliefs.
- Outcome studies show that patients recieving CBT experience fewer hallucinations and delusions than those recieving antipsychotic medication alone.
- Lower patient drop - out rates and greater patient satisfaction with CBT than antipsychotic medication.
- Effectiveness - meta - analysis found significant decreases in positive symptoms after CBT treatment.
- Most CBT studies also involve antipsychotic medciation, therefore diffucult 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.
- Ethical issues arise in placebo condition where atients are denied effective treatment.
- Psychodynamic Therapies:
- Psychoanalysis based on assumption that individuls unaware of influence of unconscious conflicts on their surrent psychological state.
- Therapsts create an alliance with patient by offering help with what patient perceives as the problem.
- All psychodynamic therapies build trust with patients by replacing harsh parental conscience with one that is more supportive.
- As patient gets healthier, they take a more active role.
Psychodynamic Therapies Evaluation:
- Meta - analysis (Gottdiener, 2000) - 66% of those recieving psychotherapy improved after treatment, while 35% didnt.
- Some forms of psychodynamic therapy can even be harmful in treatment of SZ
- research on effectiveness of psychodynamic therapy shows contradictory findings
- 'Supportive' psychotherapies appropriate when combined with antipsychotic medication.
- Psychodynamic theray = long and expensive, but has benefits in thhat it might take patients more able to seek employment.
- Methodological limitations of psychodynamic outcome studies include lack of random allocation to therapy conditions.
- SZ more common among biological relatives of person with SZ (Gottesman, 1991)
- Twin studies - (Joseph, 2000) poooled data shows concordance rate of MZ twins of 40% and DZ twins of 7%.
- Use of 'blind' diagnosis produces lower concordance rate for MZ twins, but still much higher than DZ.
- Adoption studies (Tienari et al, 2000) - if biological mothers SZ, 6.7% of adoptees also SZ (2% of controls)
- Neurons that transmit dopamine, fire too easily or too often, leading to symptoms of SZ.
- SZ - abnormally high levels of D2 receptors.
- Evidence from large doses of amphetamines (dopamine agonist) causes hallucinations and delusions.
- Antipsychotic drugs - block dopamine and eliminate symptoms.
- Parkinson's disease - treatment with L-dopa raises dopamine levels and can therefore also trigger SZ symptoms.
- Drugs can incrwase SZ symptoms as neurons try to compensate. (Haracz, 1982) found elevated dopamine levels in post - mortems of SZ who had taken medication.
- Neuroimaging studies failed to provide convincing evidence for altered doamine activity in SZ.
Genetic Factors Evaluation
- Environments of MZ twins may be more similar than for DZ twins.
- Difference in concordance rates may reflect environmental similarity rather than role of genetic factors.
- The fact that SZ runs in families may be due to factors that have nothing to do with heritability. e.g. EE
- Adopted children from SZ backgrounds, may be adopted by particular type of adoptive parent, making conclusions difficult to draw.
- Many studies have to include ' schizophrenia spectrum disordes' to show genetic influences.
- Evolutionary perspectives - SZ may have adaptive advantages e.g. group splitting hypothesis.
- psychodynamic view of SZ - result of regression to pre ego stage and attempts to re -e stablish ego control.
- som SZ symptoms relect infantile state, other symptoms are an attempt to re - establish control.
- Further features of disorder appears as individuals attempt to understand their experiences.
- They may reject feedback from others and devlop delusional beliefs.
- Very little evidence to support psychodynamic view of SZ.
- Behaviour of parents assumed to be key influence in development of SZ but may be consequence rather than cause.
- Cognitive explanation supported by neurophysiological evidence. (Meyer - Lindeneberg, et al, 2002)
Socio - cultural factors:
- Prior to SZ episode, patients report 2x as many stressful life events
- Double - blind theory: contradictory messages from parents precent coherent construction of reality, leads to SZ syptoms.
- EE - family communication style involving criticism, hostility and emotional over - involvement.
- Leads to stress beyond impared coping mechanisms and so SZ.
- Labelling theory - symptomsof SZ seen as devient from rules ascribed to normal experience. Diagnostic label leads to self fulfillinng prophecy.
Socio - culural Factors Evaluation:
- some evidence challenges link between life events and SZ. evidence for link is only correlational, not causal.
- Importance of family relationships in development of SZ shown in adoption study by (Tienari et al, 1994)
- Double - blind theory = supported by (Berger, 1965) - SZ recalled more double - blind statements from mothers
- EE - has led to effective therapy for relatives.
- (Scheff, 1974) - 13 of 18 studies consistent with predictions of labelling theory.
- Link supported both retrospective (Brown and Birley, 1968) and prospective (Hirsch et al, 1996) studeis.
- EE effects much less common in non - individualist cultures.