Schizophrenia

• Negative symptoms of schizophrenia

  • Speech Poverty (Alogia)
  • Avolition
• Neural correlates


  Changes in neuronal events and mechanisms that result in the characteristic symptoms of a disorder
• Validity refers to the accuracy of a measurement- whether or not an observed effect is genuine
• Positive symptoms of schizophrenia


  • Delusions
  • Hallucinations
• Double bind theory


  Refers to receiving contradictory information from a family member, such as being told they love them
• Reliability refers to the consistency of a measure, as the same data should be produced by a measurement if it is taken on successive occasions
• Dopamine hypothesis as an explanation for schizophrenia

  When the neurotransmitter dopamine is in excess in regions of the brain, positive symptoms of schizophrenia can be observed
• Interactionist Approach to Schizophrenia

  Schizophrenia develops in individuals who have a genetic vulnerability (diathesis), following an activating event (stress)
• How do antipsychotics work?
• Why are drug therapies preferred to other therapies?
• Antipsychotics have affinity for D2 receptors, believed to reduce the risk of side effects
• Symptom overlap refers to the fact that some symptoms may not be unique to one disorder, but rather shared amongst many disorders
• Why is Token Economy considered unethical?
• Antipsychotics are dopamine antagonists that decrease the activity of dopamine by blocking receptors
• Define comorbidity
• Comorbidity refers to the extent to which two or more conditions occur simultaneously in a patient, like schizophrenia and depression
• Define symptom overlap
• Token Economy

  1. Desirable behaviors are encouraged by the use of reinforcements

  2. Rewards are given in exchange for tokens earned when desirable behaviors are performed
• Reasons why drug therapies are preferred

  • They are effective
  • They are cheap
  • They require less effort on the part of the patients, increasing the chances of them persisting in the treatment
• What is meant by ‘Token Economy’?
• Reasons why Token Economy is considered unethical


  • For token economy to work, psychiatrists have to be in control over food and other things that act as primary reinforcers
  • In order for patients to have access to these things, they have to exchange tokens given to them by the psychiatrists
  • This contradicts the notion that all humans have the right to things like privacy and food without having to earn them
• Inter-rater reliability


  Two or more health professionals come to the same diagnosis
• Criterion Validity


  Different methods of assessment come to the same diagnosis
• Co-morbidity


  Two or more conditions occur simultaneously
• Symptom overlap


  The same symptoms occur within different conditions
• Cheniaux et al (2009)


  Two psychiatrists independently diagnosed 100 patients using two different assessments
• Buckley et al (2009)


  Investigated those with schizophrenia and found they were likely to also suffer from another condition
• Gottesman (1991)


  Schizophrenia runs in families. Probability of schizophrenia = 48% between MZ twins, 46% if both parents had it and 10% between DZ twins.
• Tienari et al (2004)


  Children adopted from 19,000 Finnish mothers at birth. More likely to develop schizophrenia when biological relatives had it, but not when adoptive parents did. High EE levels also implicated in development, but only for those with a genetic risk.
• Ripke et al (2014)


  Meta-analysis of genome studies. Genetic make-up of 37,000 patients compared to 113,000 controls - 108 candidate genes associated with increased risk of schizophrenia
• Hyperdopaminergia


  High levels of dopamine in the brain's subcortex
• Hypodopaminergia


  Low levels of dopamine in the brain's cortex
• Curran et al (2004)

  Drugs that increase levels of dopamine made schizophrenia worse and induce schizophrenia like symptoms in non-schizophrenics
• Goldman-Rakik et al (2004)


  Low levels of dopamine in prefrontal cortex thought to have a role in causing negative symptoms of schizophrenia
• Moghaddam and Javitt (2012)

  High levels of glutamate contibute to symptoms of schizophrenia. The dopamine hypothesis is reductionist as it doesn't consider other neurotransmitters
• Neural Correlates


  Patterns of structure or activity in the brain that occur in conjunction with an experience
• Allen et al (2007)


  Participants listened to recordings of speech and had to identify if it was their own or not. MRI's used to scan brain.
• Allen et al (2007)


  Hallucinating schizophrenics made more errors in voice recognition and showed lower levels of activity in the superior temporal gyrus and the anterior cingulate gyrus compared to controls
• Juckel et al (2006)

  Conducted a study involving reward anticipation on 10 schizophrenic males and a matched control group.
• Juckel et al (2006)


  Found healthy males had higher levels of activity in the ventral striatum (involved in reward anticipation) than those who were schizophrenic. The lower the activity the worse the symptoms of schizophrenia.