Outline and Evaluate Biological Explanations for Schizophrenia (a* Essay, Marked by My Teacher)

1602 Words7 Pages
There appears to be a tendency for schizophrenia to run in families. This suggests that genes play a role. Gottesman found that schizophrenia is more common among biological relatives of a person with schizophrenia and also that the closer the degree of genetic relatedness, the greater the risk. Gottesman conducted family studies and showed that when both parent are schizophrenic the children have a 46% concordance rate, however, if only one parent had it, it dropped to 16% and dropped to a further 1% when the sibling of the child had schizophrenia. This suggests that a genetic factor is involved. MZ twins share 100% of their genes; DZ twins share 50% of their genes. If genes are a factor we would expect more identical twins to share the disorder than non-identical. Rosenthal took a case study which had a set of female quadruplets. They all developed schizophrenia although the onset and symptoms were very different. This could have been a result of having a troubled upbringing. This suggests a strong heritable component. Further, Joseph calculated concordance rates of 40.4% for MZ twins and 7.4% for DZ twins. However, most first degree relatives and twins share the same or similar environments so it is difficult to separate genetic and environmental influences. Because of the difficulties of disentangling genetic and environmental influences for individuals who share genes and environment, studies of genetically related individuals who have been reared apart are used. Tienari et al conducted a longitudinal study and found that out of 164 adoptees whose biological mothers had been diagnosed with schizophrenia, 11 (6.7%) also received a diagnosis of schizophrenia, compared to just four (2%) of the 197 control adoptees (born to non- schizophrenic mothers). This suggests that genes rather than the environment have caused the disorder in these cases. It supports the

More about Outline and Evaluate Biological Explanations for Schizophrenia (a* Essay, Marked by My Teacher)

Open Document