Discuss One or More Biological Explanation of Schizophrenia

However, the concordance rates for non identical (DZ) twins are 17%. Rosenthal (1963) did a case study of quadruplets (girls) and found that the concordance rates showed that all four developed schizophrenia. This evidence shows that if you are a MZ twin then your chance of contracting schizophrenia rises by 48%.
             Tianari(1991) did a study using 155 schizophrenic mothers who gave there children up for adoption. These children were compared to the same size sample of adopted children who had no family history of schizophrenia. 10.3%of children with a schizophrenic mother developed schizophrenia compare to 1.1% of those who did not have a schizophrenic mother. This shows that because 10.3% is lower than the percentage proposed by Gottesman, which was 16%. This would indicate that it might also depend on the environment. I.e. people who are brought up in a schizophrenic household are more likely to become schizophrenic.
             Concordence rates are no 100% and so it cannot purely be down to genes, therefore environmental factors cannot be ruled out. Schizophrenia definitely runs in families, and it is true to say that the more genetically similar relatives are to each other, the higher the concordance rate of contracting schizophrenia.
             The Dopamine hypothesis is biochemical explanation for the cause of schizophrenia. there is almost undoubtedly a genetic influence in determining who is most vulnerable to schizophrenia, brain biochemistry is the effect that inheriting a schizophrenic gene has upon the brain biochemistry itself. It is therefore not the gene itself that causes schizophrenia but the effect the gene has on the causal factor of schizophrenia.
             Dopamine is a naturally occurring substance in our brains and is a neurotransmitter. It is believed that too much dopamine occurring in our brains causes many of the positive symptoms of schizophrenia, including delusions, hallucinations and catatonia. This is either because there is excessive production of the chemical, or because there are not enough receptors so reuptake is limited.