Biological explanations for schizophrenia

The genetic basis of schizophrenia
Schizophrenia runs in families

• Gottesman (1991) performed a large-scale family study and found that the shared risk of identical twins developing schizophrenia is 48% compared to 17% for nonidentical twins and 9% for siblings

Individual genes are believed to be associated with risk of inheritance

• Schizophrenia is polygenic: it requires a number of genes to work in combination
• Schizophrenia is aetiologically heterogenous: different combinations of factors can lead to the condition
• Ripke et al (2014) carried out a study combining all previous data from genome-wide studies and found that 108 separate genetic variations were associated with increased risk of schizophrenia, including genes coding for the functioning of neurotransmitters including dopamine

The dopamine hypothesis
Dopamine is important in the functioning of several brain systems that may be implicated in the symptoms of…