Biological explanations for schizophrenia

Genetic factors:

• A cause of schizophrenia may be heredity 
• Those who are genetically related to someone who suffers from schizophrenia are more at risk of also suffering from the same psychotic disorder
• It is more likely that a combination og genes make an individual more vulnerable to schizophrenia 
• But this does not necessarily mean that the individual will get schizophrenia 

• Family studies:
  • Gottesman (1991) 
    • Completed a study showing the concordance rate in families were parents or siblings had schizophrenia 
    • Children with both parents with schizophrenia = 46%
    • Children with 1 parent with schizophrenia = 13%
    • Children with siblings with schizophrenia = 9% 
  • Bilogical relatives more likely to be affected by individual who has schizophrenia in family than non-bilogical relatives
  • The closer the degree of genetic relatedness, the grater the risk
• Twin studies:
  • Joseph (2004):
    • Calculated the pooled data for all schizophrenia twin studies prior 2001 showed concordance rates of:
    • 40.4% in MZ twins 
    • 7.4% for DZ twins 
  • Methodologically sound studies tend to report lower concordance rate for MZ twins than DZ twins but still support genetic position that the concordance rate for…