Evaluation of the Genetic Explanation

• The genetic explanation is supported by twin studies, which show that monozygotic twins are more likely to have schizophrenia than dizygotic twins.
• Family studies suggest that there may be a link between genetics and schizophrenia, but these findings could be due to environmental factors such as shared genes or upbringing.
• Adoption studies also support the genetic explanation as they found that adopted children with biological parents who had schizophrenia were at higher risk of developing it themselves compared to those without this family history.
• Adoption studies also support the genetic explanation as they found that adopted children with biological parents who had schizophrenia were more likely to develop it themselves compared to those without biological relatives with schizophrenia.
• However, there are limitations to these findings such as small sample sizes and lack of control over environmental factors.
• There is no single gene responsible for schizophrenia but rather multiple genes interacting together.
• However, adoption studies can only identify links between genetics and schizophrenia if both adoptive and biological families are included in the research design.
• Studies on identical triplets separated at birth showed that all three developed schizophrenia, suggesting a strong genetic component.
• Linkage analysis has identified specific chromosomes associated with an increased likelihood of developing schizophrenia, supporting the genetic explanation.
• Evaluation point to support family studies
• Evaluation point to support family studies- varma (1997)

  Varma (1997) found that 16% of the first degree relatives of people with schizophrenia developed schizophrenia compared to only 7% of the controls. this therefore supports the genetic explanation because it suggests having close relatives with SZ does significantly increase your risk of developing the disorder.
• Support of genetic explanation from twin research by Joseph (2004)


  they found a concordance rate of 40% for Mz twins compared to only just over 7% for DZ twins. this suggests more genes in common with another sufferer does increase your likelihood of developing the disorder too.
• limitation of twin research as a genetic explanation. It's possible that higher concordance rates in Mz twins were the result of being treated more similarly than dz twins who are more likely to be treated differently, making it hard to rule out environmental factors as an explanation. Furthermore, the fact that concordance rates are not 100% in mz twins suggests the enviroment must play a role too.