biological approach : genetic Flashcards
what is the genetic explanation of schizophrenia?
schizophrenia tends to run in families, but among individuals who are genetically related
the risk of developing the disorder among individuals who have family members with schizophrenia is higher than it is for those who do not
family studies
established that schizophrenia is more common among biological relatives of a person with schizophrenia, and that the closer the degree of genetic relatedness, the greater the risk
for example, in gottesman’s study, children with two schizophrenic parents had a concordance rate of 46%, children with one schizophrenic parent had a concordance rate of 13% and siblings had a concordance rate of 9%.
twin studies
if MZ (genetically identical) twins are more concordant (similar) than DZ (share 50% genes), then this suggests that the greater similarity is due to genetic factors
joseph- MZ twins (40%) and DZ twins (7%)
adoption studies - why do these studies focus on genetically related individuals reared apart?
because of the difficulties of disentangling genetic and environmental influences for individuals who share genes and environment
what did tenari’s study find to support the idea of genetic liability in SZ?
of the 164 adoptees whose biological mothers had been diagnosed with schizophrenia, 11 also received a diagnosis of schizophrenia, compared to just 4 of the 197 control adoptees (those born to non-schizophrenic mothers). the investigators concluded that these findings showed that the genetic liability to schizophrenia had been ‘decisively confirmed’
