Gottesman (1991)- found a concordate rate of 48% for MZ twins and 17% for DZ twins.
Supporting evidence
Marcusetal (1987)- found that children who developed SZ were more likely to come from high EE families.
Supporting evidence
Readetal (2001)- suggests traumatic childhood events cause changes in the developing brain that could make someone vulnerable to schizophrenia.
Research support
Research suggests vulnerabilities are also neurodevelopmental not just genetic- progressed our understanding of the disorder.
Supporting evidence
Semple et al (2005)- There is evidence to show that those who use cannabis, particularly at a younger age, have a higher than average risk of developing schizophrenia.
Limitations
It is not clear how the different risks interact and contribute to the development of SZ.
