AS Psychology Unit 2: The Biological Approach Studies.

Biological Approach Studies

Twin Study

Gottesman (1991) conducted a meta-analysis of twin studies

Method: Gottesman carried out a meta-analysis of approximately 40 twin studies.

Results: It was found that having an identical twin with schizophrenia gave you a 48% chance of developing the condition. This reduced to 17% in non-identical twins.

Conclusion: Schizophrenia has a strong genetic basis.

Evaluation: The meta-analysis was carried out on field studies, giving the research high ecological validity. Because identical twins share 100% of their genes, it might be expected that both twins would always suffer from the same condition. The fact that both twins had developed schizophrenia in only about half of the…