Genetic explanation

• What are the three genetic studies of schizophrenia?

  • Family studies
  • Twin studies
  • Adoption studies
• How are family studies used to explain schizophrenia?

  Find individuals with schizophrenia and determine whether their biological relatives are similarly effected more often than non relatives
• Give a study supporting family studies as an explanation of schizophrenia

  Gottesman (1991) found children with two schizophrenic parents had a concordance rate of 46% and those with one schizophrenic parent 13%, and siblings had 9%
• How are twin studies used to explain schizophrenia?

  If MZ twins are more concordant than DZ twins, it suggests a genetic factor
• Give a study that supports twin studies as an explanation for schizophrenia

  A meta analysis of twin studies conducted before 2001 found a combined concordance rate of 40% for MZ twins and 7% for DZ twins (Joseph, 2004)
• What are adoption studies for schizophrenia?

  Studies of genetically related individuals who have been reared separately 
• Give a study that supports adoption studies as an explanation for schizophrenia?

  Tienari et al (2000), found that of 164 adoptees with schizophrenic mothers, 11 (6.7%) also received a diagnosis, compared to just 2% of the 197 control adoptees.