Biological Explanations

• What does the Genetic Theory suggest about schizophrenia (Sz)?

  It suggests that Sz is caused by genes passed from biological parent to child.
• How does genetic relatedness affect the likelihood of developing Sz?

  The more closely related you are to someone with Sz, the more likely you are to develop it.
• How many genetic variations did Ripke (2014) find associated with the risk of Sz?

  108 separate genetic variations.
• What does it mean that Sz is polygenic?

  It means that Sz is caused by multiple genes.
• What were the concordance rates for MZ and DZ twins according to Gottesman?

  MZ twins had a concordance rate of 48% and DZ twins had a concordance rate of 17%.
• What does the concordance rate indicate about genetic explanations for Sz?

  The higher the concordance rate, the more likely genetic factors contribute to Sz.
• What does the fact that concordance rates are not 100% imply about Sz?

  It implies that other factors besides genetics must contribute to the onset of Sz.
• What was the concordance rate for MZ twins reared apart according to Gottesman & Shields (1982)?

  The concordance rate was 58%.
• What limitation did Gottesman & Shields (1982) face in their study?

  Only 12 pairs of twins were included, leading to low population validity.
• What did Heston (1966) find in his study of adopted children?

  16% of children with a biological history of schizophrenia developed the disorder.
• How does the Genain Quadruplets case support genetic explanations for Sz?

  They all suffered from Sz, indicating a genetic link, but differed in symptoms and age of onset.
• What are the strengths and weaknesses of the genetic theory of Sz?

  Strengths:

  • Leads to greater research in the field
  • Interactionist position is helpful

  
  

  Weaknesses:

  • Reductionist, narrow, and unhelpful
  • Ethical considerations are socially sensitive
• What is one application of the genetic theory in healthcare?

  Genetic counselling helps people make informed decisions about genetic diseases.
• Why can't genetic estimates definitively predict if a child will develop Sz?

  Because everyone has different additional risk factors in their environments.
• What environmental factor is mentioned as increasing the risk of Sz?

  Childhood trauma.
• What does the dopamine hypothesis suggest about Sz?

  Symptoms of Sz might be caused by abnormal levels of dopamine.
• What are some functions that dopamine affects?

  Learning, attention, memory, anxiety, sleep, movement, and motivation.
• What is hyperdopaminergia?

  Higher than usual levels of dopamine in the subcortex linked with positive symptoms.
• What is hypodopaminergia?

  Lower than usual levels of dopamine in the cortex linked with negative symptoms.
• What did Randrup and Munkvad (1966) find regarding amphetamines and Sz symptoms?

  They found that amphetamines induced schizophrenic-like symptoms in rats.
• What did Iverson find in post-mortems of patients with Sz?

  High levels of dopamine were found compared to those without Sz.
• What limitation does the correlation found by Iverson present?

  It does not establish cause and effect between Sz and dopamine levels.
• How do anti-psychotics like chloropromazine support the dopamine hypothesis?

  They decrease dopamine levels, reducing symptoms of Sz.
• What is the treatment-aetiology fallacy?

  It is the mistake of assuming that a treatment's effectiveness indicates the cause of a disorder.
• What did Davis (1974) find about drugs that increase dopamine levels?

  They can cause people to experience schizophrenic-like symptoms.
• How is Parkinson's disease related to dopamine levels?

  It is thought to be caused by decreases in dopamine.
• What do drugs used to increase dopamine levels in Parkinson's patients cause?

  They can have side effects similar to the symptoms of Sz.
• What are neural correlates?

  Measurements of brain structure or function that correlate with experiences or behaviors.
• What neural correlate is associated with positive symptoms of Sz?

  Excessive dopamine receptors found in Broca's area.
• What neural correlate is associated with negative symptoms of Sz?

  Enlarged ventricles that are 15% larger in people with Sz.
• What is a major issue regarding causation in neural correlates?

  It is unclear whether abnormalities in brain areas are causes or symptoms of Sz.
• What is biological reductionism in the context of Sz?

  It is the oversimplification of Sz as being caused solely by brain chemicals.
• What is a benefit of reductionist explanations in Sz research?

  They enable scientific research by narrowing down to simple causes.