Genetic explanation

• Genetic explanation

  The cause of schizophrenia is linked to genes
• Gottesman's family study


  • Large scale family study on schizophrenia
  • 2 SZ parents = 46%
  • 1 SZ parent = 13%
  • SZ sibling = 9%
  • High genetic similarity + links = higher chance of developing SZ.
• Tienari's adoption study


  • 164 adoptees whose biological mothers had SZ.
  • 6.7% got SZ compares to 2% of controlled adoptees
• Gottesman + Shield's twin study

  • 57 pairs of twins patient records.
  • Concordance rates:
  • MZ twins = 54%
  • DZ twins = 18%
• Why are genes are polygenic in SZ?

  There are a number of different genes that are involved in the cause of SZ.
• Gene study (Ripke et al)

  • Studied 37,000 SZ patients and 113,000 controls
  • Found 108 genetic variations associated with SZ. (including gene that codes for the neurotransmitter for dopamine)
• Limitations of Genetic explanation (alt explanation)

  • Genetics alone cannot explain SZ.
  • Family dysfunction (childhood trauma)
  • 67% of ppl with SZ had at least 1 trauma compared to 38% matched group with non-psychotic mental health issues.
• Limitation of genetic explanation (environment)

  • Twin studies + family studies.
  • Environmental factors cannot be taken away as they grew up/ live in the same environment.
  • Argument for the nature vs nurture