Biological causes of schizophrenia Flashcards
Genetic Factors AO1
believes that schiz is transmitted through hereditary means
no single ‘schiz gene’ has been found
several genes involve to increase persons vulnerability
What studies to look at the genetic factors of schiz
family studies
adoption studies
twin studies
gene mapping
how family studies study for genetics
look for concordance rates between relatives can be longitudinal
how twin studies study for genetics
concordance rates between mz & dz
how adoption studies stud for genetics
concordance rates after disengaging genes from enviromental factors
how gene mapping studies for gene mapping
looks for common genetic variations at locations on human chromosomes
Family Studies AO3
Supporting evidence
Gottemans study findings that 2 parents w schiz ha a 46% with their children and 1 parents with schiz had a 13% concordance rate in their children and brother/sisters had a 9% concordance rate in them
evidence to support it runs in families. However, could be to do with common rearing practices and shared env. etc. not hereditary linked to the family dsyfunction theory
twin studies AO3
Supporting evidence
Joseph(2004) look at the data from schiz twin and that concordance rate in mz twins was 40.45 and 7.4% in dz twins
If MZ twins had a greater concordance rate than DZ suggests greater similarly is due to genetic factors
However if genes cause schiz should be 100% suggest that it shows the environmental differences that distinguish the two types of twins
adoption studies AO3
Supporting evidence
uses studies of genetically related indvdls that have been reared apart
(Tiernan) 164 adoptees w schiz mothers only 11 (6.7%) received schiz diagnosis compared to just 4 (2%) of 197 control adoptees (no mother with schiz shows that genetic liability to schizophrenia had been decisively confirmed
Used to disentangle nature and nuture however they believed there was no difference with those who adopt a child from schiz parents are no different from adoptive parents who adopt children with normal background. Becuase the adoptive parents would be told that they came from schiz parents which could be reflective in their behaviour
Gene mapping AO3
research suggest schiz could have genes that increase vulnerability
Benzel(2007)- NRG3 gene variants interact with NRG & ERRB4 gene variants to create suscepitibilty
Offers the possibility of developing tests to identify high risk indvdls though this raises socially sensitive and ethical concerns
But yet no one gene exists that is ultimately linked to every sufferer
Genetic Factors AO3
The Dopamine Hypothesis AO1
Synder argued if too much dopamine was released it can lead to the onset of sz. Over activity of this neurotransmitter can cause hallucinations + delusions. Ppl w/ SZ have an abnormally high no. of D2 receptors- more dopamine binding and neurons fired.
