Schizophrenia Chapter Summary

Nature of Schizophrenia:

• Profound disruption of cognition and emotion
• Affects language, perception, affect and sense of self
• Association with violence = media invention
• 8% of schizophrenics commit a serious act of violence
• Less than other mental disorders 

Diagnostic Criteria:

• Positive symptoms = excess or distortion of normal symptoms - delusions, experience of control, hallucinations and disordered thinking
• Negative syptoms = loss of normal functions - affective flattening, alogia and avolition
• Diagnosis:
  •  
    • Two or more positive symptoms 
    • Social/occupational dysfunction
    • At least six months
    • Exclusion of mood disorders
    • Exclusion of organic cause 

Reliability:

• Extent to which psychiatrists can agree on the same diagnosis
   
• DSM claims increased reliability of diagnosis
   
• Whaley (2001) - inter-rater reliability as low as 0.11
   
• Klosterkotter et al (1994) - positive symptoms are more useful for diagnosis
   
• Mojabi and Nicholson (1995) - low inter-rater reliability of 'bizzare' vs 'non-bizzare' symptoms
   
• Rosenhan's study highlights the problem - Being sane in insane places

Validity:

• Concerns over what schizophrenia really is
• First-rank symptoms distinguish schizophrenia from other disorders
• Also found in other disorders such as DID
• Little evidence of shared prognosis in schizophrenia
• Low predictive validity 

Synoptic Link:

Copeland (1971) - reliability challenged by difference between UK and US diagnoses 

Genetic Factors:

• Gottesman (1991) - more common among biological relatives
• Joseph (2000) found concordance rate of 40% for MZ twins and 7% for DZ
• 'Blind' diagnosis produces much lower concordance rate for MZ but still higher than DZ
• Tienari et al (2000) if biological mother schizophrenic, 6% of adoptees are also schizophrenic, with 2% of controls

Evaluation:

• Environments for MZ twins may be more similar than DZ
• Differences in concordance rates may reflect environmental similarity rather than role of genetic factors 
• Adopted childen 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/often leading to symptoms
• Schizophrenics have abormally high levels of D2 receptors
• Amphetamines cause hallucinations and delusions (dopamine antagonist)
• Antipsychotic drugs - block dopamine and eliminate symptoms
• Parkinson's disease - treatment raises dopamine levels and trigger schizophrenic symptoms

Evaluation:

• Drugs can increase schizophrenia symptoms as neurons try to compensate 
• Haracz (1982) found elevated dopamine levels in post-mortems of schizophrenics who had taken medication before death
• Neuroimaging studies failed to provide convincing evidence for altered dopamine activity in schizophrenics 

Enlarged Ventricles:

• 15% bigger in schizophrenics than non-schizophrenics
• Display negative rather than positive symptoms
• Result of poor brain development or tissue damaging

Evaluation:

• Meta-analysis found substantial overlap in ventricle size among schizophrenics and control populations
• Enlarged ventricles may be due to effects of antipsychotic medication

Synoptic Links:

• Many studies have to show 'schizophrenia spectrum disorders' to show genetic influences
• Evolutionary perspective - schizophrenia may have an adaptive advantage (group splitting hypothesis) 

Psychological Theories:

• Psychodynamic view: result of regression to a pre-ego stage and atempts to re-establish ego control
• Some symptoms reflect infantile state, others are an attempt to re-establish control
• Further features appear as they try to understand their experiences
• May reject feedback from others and develop delusional beliefs

Evaluation:

• Very little evidence to support psychodynamic view
• Behaviour of parents = key influence in development but may be a consequence rather than a cause

Socio-Cultural Factors:

• Patients report twice as many stressful life events prior to schizophrenic episode
• Double-bind theory - contradictory messages from parents
• Expressed Emotion - family communication style 
• Leads to stress beyond impaired coping mechanisms
• Labelling theory - symptoms of schizophrenia seen as deviant from the rules

Evaluation:

• Link between life events is only correlational
• Berger (1965) schizophrenics recall more double-bind statements from mothers
• Scheff (1974) - 13 out of 18 studies consistent with predictions of labelling theory 

Synoptic Link:

• Must less common in non-individualistic cultures (EE)

Anti-psychotic medication:

• Conventional = reduce effects of dopamine and so reduce symptoms
• Bind to D2 dopamine receptors but do not stimulate them
• Atypical = temporarily occupy D2 receptors then dissociate to allow normal transmission
• Leads to lower levels of side effects

Evaluation:

• Davis et al (1980) higher relapse rates in patients who had placebo rather than drug
• More effective for hostile home environments
• Conventional = 30% develop TD
• Motivational deficits - prevents positive actions
• Leucht et al (1999) - superiority of atypical over conventional only moderate
• Atypical = marginal support for effectiveness with negative symptoms
• Atypical = lower TD rates
• Patients more likely to continue with less side effects 

ECT:

• Karagulla (1950) - first studies were disappointing
• Recovery lower than control group
• Tharyan and Adams (2005) - found 'real' ECT more effective than 'sham' ECT
• Combined with medication for rapid reduction in symptoms

Evaluation:

• Effectiveness = inconsistent
• APA study found no difference between effects of ECT and antipsychotic medication
• Sarita et al (1998) - no difference in symptom reduction between ECT and simulated ECT
• Risks of ECT
• Use has declined 

Synoptic Links:

• Ross and Read (2004) - placebo not a fair test because proportion of relapses explain by withdrawal effects
• Ethical issues - human rights issues associated with TD 

CBT:

• Patients trace back origins of symptoms to understand how they developed
• Evaluate content of delusions/hallucinations
• Develop own alternatives to maladaptive beliefs
• Outcome studies show that patients receving CBT experience fewer hallucinations/delusions than those recieving antipsychotic medication alone 
• Lower patient drop-out rates and greater satisfaction 

Evaluation:

• Meta-analysis found significant decreases in positive symptoms after CBT
• Most studies involved antipsychotic medication - hard to judge CBT alone
• Older patients less likely to benefit 

Psychodynamic Therapies:

• Based on assumption that individuals unaware of influence of unconsious conflicts on their current psychological state
• Creates an alliance with patients by offering to help with the problem
• Build trust by replacing harsh parental conscience with more supportive one
• Patients takes more active role

Evaluation:

• Gottdiener (2000) - 66% improved after treatment, 35% didn't
• Some forms can be harmful
• Contradictory findings
• Appropriate when combined with medication
• Long and expensive - may have benefits in that it helps patient to seek employment 

Synoptic Links:

• Methodological limitations of outcome studies - lack of random allocation
• Ethical issues - placebo as denied effective treatment