Slides in this set
According to Gottesman (1991) schizophrenia is an inherited illness caused by a faulty gene.
Concordance Rate (CR) the likelihood of somebody developing schizophrenia
Gottesman looked at mozygotic (MZ) (identical) and dyzagotic (DZ) (non-identical) twins.
He found a CR of 48% in MZ twins and CR of 17% in DZ twins.
Why are these figures so important? Although they show a relationship between
schizophrenia and genetics, this relationship is only suggested. As of yet there is no research
to suggest that there is one single faulty gene to cause schizophrenia. There exist many other
explanations as to why this illness develops.
Identical twins share 100% of their genes, therefore, according to the theory, there should
be a 100% CR in MZ twins. Likewise, there should be a 50% in DZ twins. The fact that this is
not would suggest that there are other contributing factors to schizophrenia (the nurture of
In criticism of this however, the same CR was found in cases where the twins were brought
A more current study taking place in 2002 (Cardno) found a significantly smaller CR, with
only CR of 26.5% in MZ and no CR in DZ twins.…read more
Tienari looked at 155 adopted children in Findland.
For children which schizophrenic biological mothers
there was a 10% CR. For those without schizophrenic
mothers there was a mere 1%.
Gottesman discovered that if both of your parents
were schizophrenic you would have a CR of 46%. The
closer the relative, the higher CR rate.…read more