Biological explanation: The Genetic Explanation of Schizo

• The genetic explanation for schizophrenia

  • suggests SCZ is inherited and therefore runs in families (Gottesman 1991)
  • proposes SCZ is polygenic, meaning it is caused by numerous genes
  • each candidate gene is proposed to increase the risk of developing SCZ by a small amount (Ripke)
• Gottesman (1991)

  Gottesman found a strong correlation between the level of genetic similarity between two individuals and their shared risk of SCZ.
• What did Gottesman find?


  • a 48% concordance rate for SCZ in MZ twins (who share 100% of their genetics)
  • 17% in DZ twin (who share 50% of their genetics)
  • 5% between a person with SCZ and their grandparent (who share 25% of genes)
• What was Gottsman conclusion

  With the figures, when compared to the 1% risk of SCZ in the general population, suggests the higher the genetic similarity to an individual with SCZ, the more likely you are to also develop it.
• what did Ripke (2014) find in people with SCZ

  Found 108 genetic variations in people with SCZ
• Evaluating the genetic explanation of schizophrenia

  • it is biologically deterministic
  • that Gottesman’s (1991) study supports the role of genetics in schizophrenia can equally be explained by environmental influences rather than genetics
  • there is supporting evidence that is better able to distinguish between genetic and environmental causes
  • research suggests even if the disorder does have a genetic basis, it is not a sole cause of the disorder