AO1

• Genetic Correlates: What does the constant prevalence rate of 1% for schizophrenia suggest?

  It suggests a genetic cause for schizophrenia.
• Genetic Correlates: Three types of studies used to investigate genetic causes of schizophrenia:

  • Twin studies
  • Adoption studies
  • Family studies.
• Genetic Correlates: What did Joseph's twin study find about schizophrenia?


  • Monozygotic twins had a 40.4% concordance rate
  • Dizygotic twins had a 7.4% concordance rate.
  • Suggests that the more genetically similar individuals are, the more likely they are to develop the disorder
• Genetic Correlates: What did Tienari's adoption study find about schizophrenia?


  • Looked at 164 adoptees whose biological mothers had a diagnosis of schizophrenia
  • 11 adoptees (6.7% of sample) with schizophrenic mother received a diagnosis of schizophrenia, compared to 2% in the control group.
• Genetic Correlates: Why are adoption studies considered an improvement over other genetic studies of schizophrenia?

  They eliminate the influence of the family environment, isolating genetic factors.
• Genetic Correlates: What did Gottesman's family study find about schizophrenia?


  • Reviewed different families with cases of schizophrenia
  • Found that children with two schizophrenic parents had 46% chance of developing schizophrenia
  • Children with one schizophrenic parent had 13% chance of developing schizophrenia
  • Children with schizophrenic siblings had 9% chance of developing schizophrenia
  • Suggests that the more genetically similar individuals are, the more likely they are to develop the disorder
• Neural Correlates: Which cortex is impaired in individuals with schizophrenia?

  The Prefrontal Cortex, which is involved in problem-solving and cognitive functions
• Neural Correlates: How is grey matter affected in individuals with schizophrenia?

  • There is a reduced volume of grey matter, particularly in the temporal and frontal lobes
  • Hulshoff: The greater the tissue loss, the worse the symptoms
• Neural Correlates: What structural brain abnormality is common in individuals with schizophrenia, especially those with negative symptoms?

  Enlarged Ventricles
• Neural Correlates: What does the dopamine hypothesis suggest about the role of dopamine in schizophrenia?

  • Excess dopamine causes positive symptoms of schizophrenia as neurons fires too easily and too often
  • Individuals with schizophrenia have abnormally high numbers of dopamine receptors resulting in more dopamine binding onto post-synaptic neurons
• Neural Correlates: How do amphetamines support the dopamine hypothesis?

  Amphetamines (agonists): stimulate nerve cells containing dopamine, so when healthy patients are given it, they display behaviours similar to positive symptoms, but when they stop taking it, the positive symptoms stop.
• Neural Correlates: How do antipsychotics support the dopamine hypothesis?

  Antipsychotics (antagonists): inhibit the activity of dopamine, so when people take it, the positive symptoms of schizophrenia stop e.g inhibit hallucinations
• Neural Correlates: What does the revised dopamine hypothesis by Davis and Kahn propose?

  PET Scans show that positive symptoms are due to excess dopamine in mesolimbic pathways, and negative symptoms are due to dopamine deficits in mesocortical pathways.
• Neural Correlates: What role does the D2 receptor play in schizophrenia?

  Malfunction of the D2 receptor can cause dopamine to remain active for longer, contributing to schizophrenia symptoms.