Schizophrenia

• Schizophrenia is a serious mental disorder experienced by 1% of the world
• we identify schizophrenia by clustering symptoms
• the two systems for classification of a disorder are ICD-10 and DSM-5
• DSM-5 only classifies using positive symptoms
• ICD-10 uses two or more negative symptoms to classify schizophrenia
• positive symptoms are additional experiences such as hallucinations and delusions
• negative symptoms involve a loss of a usual abilities and experiences such as speech poverty and abolition.
• speech poverty is changes in speech patterns
• avolition is finding it difficult to keep up with goal directed activity
• Issues in diagnosis and classification

  strength : good reliability

  • consistent
  • different clinicians reach the same diagnosis for the same induvidual (inter rater reliability)
• Issues in diagnosis and classification

  limitation : low validity

  • whether we assess what we are trying to assess
  • psychologist has two psychiatrist independently diagnose 100 patients using the two manuals
  • 68 diagnosed under ICD and 39 under DSM
  • either over or under diagnosed depending on classification system
• Issues in diagnosis and classification

  limitation : co-morbidity

  • Sz often diagnosed with other conditions
  • Sz may not be as distinct a condition and makes a problem with diagnostic
• Issues in diagnosis and classification

  limitation : gender bias in diagnosis

  • 1980’s men have been diagnosed with Sz more commonly then women
  • women less vulnerable than men - maybe because of genetic factors
  • women may not be receiving treatment required —> as they function better
• Issues in diagnosis and classification

  limitation : culture bias

  • symptoms in Sz have different meanings in other cultures
  • hearing voices
  • over interpretation in black British people (Escobar) = discriminated in the diagnostic system
• Issues in diagnosis and classification

  limitation : symptom overlap

  • symptoms overlap with other conditions
  • Sz and bipolar disorder involve positive and negative symptoms
  • suggests that they may be variation of singular condition
  • hard to diagnose
• Family studies

  • confirmed an increased risk due to genetics
  • Gottesmen
  • 48% chance to develop if an identical twin suffers
  • correlation as most families share similar environments
• Candidate genes

  • polygenic - number of different genes are involved
  • aetiologically heterogeneous meaning different combinations of genes can develop the disorder
  • Ripke - meta analysis - 37000 people with Sz compared with control group
• what is it called when different combination of gene scan cause a condition?

  aetiologically heterogenous
• what is the term for when a number of genes are involved in a condition?

  Polygenic
• the role of a mutation :

  • could be caused by a mutation in parental DNA
  • evidence from positive correlations between paternal age and risk of Sz (Brown)
• OG dopamine hypothesis

  • discovery = drugs used to treat Parkinson’s disease help Sz patients
  • Sz might be due to high levels of dopamine in subcortical regions of the brain = hyperdopaminergia
• Updated dopamine hypothesis

  • addition of hypodopaminergia = low levels of dopamine in the brain
  • Howes - genetic variations and early experiences of stress (both psychological + physical) make someone more sensitive to cortical hypopaminergia and hyperdominergia
• genetic basis evaluation

  • research support = strength
  • gottesman - risk increases with genetic similarity to family members
  • tienari - biological children of parents with Sz are at heightened risk even growing up with adoptive parents
  • Hilker - showed concordance rates of 33% for identical twins and 7% for non identical twins
• genetic basis evaluation

  environmental factors - limitation

  • environmental factors also increase the risk
  • both biological and psychological influences
  • include - birth complications + smoking cannabis + childhood trauma = more vulnerable
• Neural correlates evaluation

  evidence for dopamine [DA] - strength

  • Drugs that increase DA = worsen symptoms
  • Drugs that reduce DA = reduce intensity of symptoms
  • Some candidate genes act on the production of DA and DA receptors
• Neural correlates evaluation

  glutamate - limitation

  • postmortem + live scanning studies show raised levels of glutamate up several brain regions
  • several candidate genes for Sz are believed to be involved in glutamate production + processing
• Family dysfunction - schizophrenic mother

  • Fromm-Reichmann proposed this idea
  • meant to be cold rejecting and controlling
  • family climate = tense —> distrust which can lead to paranoia and delusions
• Family dysfunction - Double~blind theory

  • Bateson agreed with family climate is the onset to Sz
  • find themselves trapped in situations where they think they are always doing wrong
  • when wrong = often, they are punished by withdrawal of love
  • understanding of world is confusing = disorganised thinking and paranoid delusions
• family dysfunction - expressed emotion

  • emotion expressed towards patients = negative emotion
  • verbal criticism
  • hostility
  • emotional over involvement
  • source of stress that can trigger onset
• cognitive explanations - dysfunctional thinking

  • disruption to the normal thought process
  • reduced though process in the ventral striatum is associated w/ negative symptoms
  • reduced processing in the temporal and cigulate gyri are associated w/ hallucinations
• cognitive explantations - meta representation dysfunction

  • inability
  • to reflect on thoughts and behaviour
  • to insight own intentions and goals
  • To interpret actions of others
  • explains voices + hallucinations + delusions
• Cognitive explanations : central control dysfunction

  • Inability to suppress automated thoughts
  • Inability to suppress speech triggered by other thoughts
  • Explains speech poverty
• Evaluation - family dysfunction

  research support

  • Read et al
  • adults with Sz more likely to be insecurely attached
  • 69% women + 59% men with Sz have a history of physical + sexual abuse
  • more research
  • most adults with Sz report at least one childhood trauma
• Evaluation - family dysfunction

  Explanations lack support

  • No evidence on Sz mothers and double blind
  • based on clinical observations and informal assessment of personalities of mothers = no systematic evidence
  • Measured patterns in communications of family’s w/ and w/o a sz child —> no difference
• Evaluation - family dysfunction

  family blaming - limitation

  • explanations blame onset onto families
  • already suffering w/ a child with Sz then getting blamed for the condition
• Evaluation - cognitive explanations

  research support

  • Stirling
  • compared cognitive tasks performed by 60 people w and w/o Sz
  • Sz patients took twice as long to complete the task —> central control dysfunction
• Evaluation - cognitive explanations

  proximal explanation

  • Only explain proximal origins of symptoms (what is happening now)
  • doesn’t link between the origins to what is happening now such as childhood trauma —> dysfunctional thinking
• Evaluation - cognitive explanations

  reductionist

  • Ignores other factors and explains a complex disorder through dysfunctional thinking
  • many others layers that form this disorder cannot look at them as separate parts
• What drugs are most commonly used to treat Sz?

  antipsychotics
• A person with psychosis experiences some loss of contact with reality