Twin studies

• Identical twins share 100% if their genes. In theory if schiz has purely genetic basis and if one twin suffers the other should too

  Non-identical twins share 50% of their genes
• Gottesman did a meta-analysis on twin studies
• Gottesman - Meta-analysis of twin studies - method

  • Gottesman carried meta-analysis on 40 twin studies
• Gottesman - Meta-analysis of twin studies - Findings

  • Identical twins share 48% chance of Schiz
  • Non-identical twins share 17% chance of Schiz
• Gottesman - Meta-analysis of twin studies - Conclusion

  • Schizophrenia has a genetic basis
• Gottesman - Meta-analysis of twin studies - Evaluation

  • Carried out on field studies
  • High-ecological validity
  • Both twins developing schiz in half of cases means other factors are involved
  • Identical twins treated more similarly than non-identical twins
  • Family environment is a factor