Schizophrenia

• Symptoms and diagnosis

  • Suffered by 1% of the world population
  • More common in men, cities and working class
  • Can interfere with everyday tasks
• Classification

  • International Classification of Disease 10 (ICD-10) - generated by WHO
  • DSM-5 - developed by American Psychiatric Association (ASA)
• Diagnosis

  • Positive symptoms - atypical, experienced in addition to normal experiences e.g. hallucinations, delusions
  • Negative symptoms - atypical experiences that represent a loss of usual experiences e.g. avolition, speech poverty
• Hallucinations

  • Can bear relationship to the environment or no relationship at all
  • e.g. voices talking to the sufferer or distorted facial expressions
• Delusions

  • Irrational beliefs, can lead to aggression
  • e.g. being hunted by aliens or having superpowers
• Avolition

  • "Apathy"
  • Difficult to keep up with goal-directed activity
  • e.g. poor hygiene, lack of persistence in work/education, lack of energy
• Speech poverty

  • Reduction in amount/quality of speech
  • Delay in verbal responses during conversation
  • DSM-5 emphasises speech disorganisation
• Evaluation of the classification and diagnosis of Sz

  Reliability

  • Means consistency
  • Inter-rater reliability, where assessors agree on their assessments
  • 2 mental health professionals agree on their diagnosis
• Evaluation of the classification and diagnosis of Sz

  Validity

  • The extent to which we are measuring what was intended
  • Criterion validity, do different assessment systems arrive at the same assessment
  • Sz is much more likely to be diagnosed under ICD-10 than DSM-5
  • Poor validity
• Evaluation of the classification and diagnosis of Sz

  Co-morbidity

  • Phenomenon where 2 or more conditions occur together
  • If conditions occur together a lot of the time, it calls into question the validity of the diagnosis and classification as they may actually be a single condition
  • 50% of people with Sz also have depression
  • 47% abuse substances
  • 29% have PTSD
  • 23% have OCD
  • Maybe Sz could be a severe case of depression
  • May be better to class them as a single condition
• Evaluation of the classification and diagnosis of Sz

  Symptom overlap

  • Sz and BPD both involve delusions and avolition
  • Calls into question the validity of classification and diagnosis
  • Under ICD-10, the person may be diagnosed with Sz
  • Under DSM-5, the person may be diagnosed with BPD
  • Suggests they may just be one condition
• Genetic explanation

  Family studies

  • Gottesman
  • Risk of Sz increases in line with genetic similarity
  • Monozygotic twins = 48%
  • Fraternal twins = 17%
  • General population = 1%
• Candidate gene

  • Polygenic - the most likely genes would be those coding for neurotransmitters
  • Aetiologically heterogenous - different combinations of factors (including genetic variation) can lead to Sz
  • Ripke et al. (2014)
  • Combined previous data from all genome-wide studies of Sz
  • Genetic make-up of 37,000 compared with 113,000 controls
  • 108 separate genetic variations associated with increased risk of Sz
• Mutation

  • Can take place due to mutations in parental DNA
  • Due to radiation, poison, viral infection
  • Positive correlation between paternal age (higher risk of mutation) and risk of Sz
  • Under 25 = 0.7%
  • Over 50 = Over 2%
  • Brown et al. (2002)
  • Correlation, not cause and effect
• Genetic explanations

  Evaluation

  • Clear evidence to show environmental factors also increase the risk of developing Sz
  • Biological factors = birth complications, smoking
  • Psychological factors = childhood trauma
  • 67% of people with Sz reported a traumatic event
  • 37% of a control group with non-psychotic mental issues reported the same
  • Genetic factors alone cannot provide a complete explanation
• Genetic explanations

  Evaluation

  • Research support
  • Gottesman (1991)
  • Risk for Sz increased with genetic similarity
  • Identical twins = 48%
  • Fraternal twins = 17%
  • General population = 1%
  • Shows some individuals are more vulnerable due to their genetic make-up
• Neural correlates

  • Neurotransmitter dopamine
  • Patterns of structure/activity in the brain that occur in conjunction with an experience and may be implicated in the origins of the experience
  • Avolition - loss of motivation, certain regions of the brain (ventral striatum), negative correlation between activity levels and negative symptoms
  • Hallucinations - superior temporal gyrus and anterior cingulate gyrus, lower levels of activation found in those hallucination vs a control
• Dopamine hypothesis

  • Original - possible roles of high levels of dopamine in the subcortex
  • Hyperdopaminergia
  • DA receptors in Broca's area may be associated with speech poverty and auditory hallucinations
  • Modern - focused on low levels of DA in the cortex
  • Rakic et al. (2004) identified a role for low levels in the PFC in negative symptoms
  • Hypodopaminergia
  • Suggests hypodopaminergia leads to subcortical hyperdopaminergia
  • Genetic variations and early experiences of stress make people more sensitive to cortical hypodopaminergia
  • To increase the levels, subcortical hyperdopaminergia
• Dopamine hypothesis

  Evaluation

  • Amphetamines can increase dopamine and worsen symptoms in those with Sz and induce symptoms in those without
  • Antipsychotic drugs reduce DA activity and reduce the symptoms
  • Some candidate genes act on the production of DA or DA receptors
  • Strongly suggests that DA is involved
• Dopamine hypothesis

  Evaluation

  • Evidence for the central role of glutamate
  • Post-mortem and live-scanning studies found raised levels for the NT glutamate in several brain regions of those with Sz
  • Several candidate genes for Sz believed to be involved glutamate production and processing
  • An equally strong case can be made for other NTs
• Before drug therapy

  • Before 1950s
  • "Safe and supportive" environment in the form of a long-stay psychiatric hospital
  • Hoping for some improvement
• Drug therapy

  • Antipsychotic drugs - used to reduce positive symptoms of psychotic disorders e.g. Sz
  • Can be short or long term
  • Some can take a short course and stop without the return of Sz
  • Others may require antipsychotics for life
• Typical drugs (1st generation)

  • Used since 1950s
  • Dopamine antagonists - combat positive symptoms
  • Chlorpromazine
• Atypical drugs (2nd generation)

  • Target a range of NTs e.g. DA and serotonin
  • 1970s
  • Combat positive symptoms although may affect negative symptoms
  • Clozapine and risperidone
• Chlorpromazine

  • Strong correlation between chlorpromazine and the DA hypothesis
  • Work by acting as an antagonist of DA
  • Blocks receptors, reducing the action
  • Normalises neurotransmission, reducing hallucinations
  • Effective sedative, related to effects on histamine receptors
• Clozapine

  • Binds to DA receptors
  • Similar to chlorpromazine
  • Acts on serotonin and glutamate receptors
  • Improved mood and reduced depression and anxiety
  • May improve cognitive functioning
• Risperidone

  • Binds to DA and serotonin receptors
  • Binds more strongly to DA receptors than clozapine so is effective in smaller doses
  • Fewer side effects
• Evaluation of drug therapy

  Meta-analysis

  • Studies comparing effects of chlorpromazine to control conditions and found it was better in overall functioning and reduced symptom severity more than a placebo
  • Another study concluded clozapine is 30-50% more effective in treatment-resistant cases where typical antipsychotics have failed
  • Shows both typical and atypical therapies are effective
• Evaluation of drug therapy

  Validity

  • Most studies are on short-term effects
  • Some successful studies have had their data published multiple times, exaggerating the size of the evidence
  • As antipsychotics have a calming effect, it is easy to demonstrate they have a positive effect on Sz sufferers
  • Casts doubt on the validity of the claim that drug therapy is an effective method for treating Sz
• Evaluation of drug therapy

  Side effects

  • Patients reported dizziness, sleepiness and weight gain
  • Long term use can result in tardive dyskinesia (caused by DA supersensitivity)
  • Results in involuntary facial movements
  • Most serious side effect is NMS, believed to be when the drug blocks DA action in the hypothalamus
  • Results in high temperature, delirium, coma and fatality
  • Antipsychotics can do harm and good
  • Sufferers who experience these may avoid such treatment, making it ineffective
• Psychological explanation

  Family dysfunction explanations

  • Sz is caused by abnormal patterns of communication within the family
  • Advocates family therapy as treatment, where abnormal communication patterns can be pointed out and changed
• Schizophrenogenic mother

  • Fromm-Reichman (1948)
  • Psychodynamic explanation for Sz, based on reports from patients
  • Patients spoke about a particular type of parent (Sz-causing) who were cold, rejecting and controlling
  • Creates an environment characterised by tension and secrecy
  • Leads to distrust that later develops into paranoid delusions, then Sz
• Double bind theory

  • Bateson et al. (1972)
  • Communication style within a family
  • Child regularly finds themselves trapped in situations where they fear doing the wrong thing, but receive mixed signals about what this is and is unable to seek clarification
  • When wrong, they are punished by withdrawal of love
  • Leaves them with an understanding of the world as confusing and dangerous
  • Reflected in symptoms: disorganised thinking and paranoid delusions
• Expressed emotion

  • The level of (negative) emotion expressed towards a patient by their carers
  • Verbal criticism
  • Hostility towards the patient
  • Emotional over-involvement in the life of the patient
  • Primarily an explanation for Sz relapse
  • Also believed to be a trigger for the onset of Sz in someone who is already vulnerable (diathesis-stress)
• Psychological explanations evaluation

  Linking family dysfunction to Sz

  • Llebel et al. (1993)
  • Claims it is how patients perceive the behaviour of relatives that is important
  • In cases where high expressed emotion behaviours are not perceived as being negative or stressful, patients are less affected
  • Tells us family dysfunction alone does not influence Sz
  • Rather, it is the way it is perceived
  • However, Berger (1965) found Sz sufferers reported a higher recall of double bind statements by their mothers than non-Sz sufferers
  • Tells us double-bind statements influence Sz
  • Provides support
• Psychological explanations evaluation

  Limited research support

  • Little evidence for Schizophrenogenic Mother and double bind statements
  • What evidence there is suffers from methodological flaws
  • Means that the explanation only has limited research basis
  • Might not tell us much about the link between family dysfunction and Sz
• Psychological explanations evaluation

  Socially sensitive theory

  • Blames parents for their child's Sz
  • Already having to watch their children experience Sz and taking responsibility for their care adds insult to injury
  • A psychological theory should cause no harm to people
  • Theories like Schizophrenogenic Mother and double bind have caused harm
  • Means that research into family dysfunction is controversial
• Cognitive explanations

  • Associated with several types of dysfunctional thought processing
  • Research has found a link between specific areas of the brain and lower levels of thought processing and hallucinations
  • Lower-than-usual levels of processing suggests that cognition is likely to be impaired
• Frith et al. (1992)

  Metarepresentation

  • Ability to reflect on thoughts and behaviour
  • Allows us to interpret the actions of others
  • Disrupts our ability to recognise our own actions as being carried out by ourselves rather than someone else
  • Explains hallucinations and delusions
• Frith et al. (1992)

  Central control

  • Ability to suppress automatic responses
  • Disorganised speech and thought disorder may result from the inability to suppress automatic thoughts and speech