Schizophrenia- Biological explanations Flashcards
How is SZ polygenic and what does this mean ?
There is more than one gene responsible for SZ presentation
What did Gottesman find about the heritability of SZ ?
The more genes a person shares with a schizophrenic relative, the more likely they are to develop it themselves
How do twin studies support that SZ is genetic ?
Gottesman conducted a meta analysis of 40 twin studies and found:
- MZ twins have a 48%
- DZ twins have a 17%
How do adoption studies support that SZ is genetic ?
Tienari identified 155 adopted children who’s biological mothers had been diagnosed with SZ and compared them with a control group of adopted children with no family history of SZ.
- 6.7% of adopted group developed SZ
- 2% of control group
How many genes were found to be linked to SZ ?
Over 100, this was found by the PGC with a sample size of 37,000 people
What are neural correlates ?
Patterns in the structure or activity in the brain linked to an experience
What is the dopamine hypothesis ?
The theory that SZ is due to abnormal dopamine activity
What is hyperdopaminergia ?
High dopamine activity
What areas of the brain have been linked to hyperdopaminergia and what symptoms can this explain ?
Subcortical areas such as Brocas area, this can be linked to positive symptoms such as hallucinations and poverty of speech
What is hypodopaminergia ?
Low dopamine activity
What areas of the brain have been linked to hypodopaminergia and what symptoms can this explain ?
Cortex areas such as the prefrontal cortex, this can be linked to negative symptoms such as cognitive symptoms and difficulty making decisions
What are enlarged ventricles ?
Ventricles are fluid filled cavities in the brain that are larger in schizophrenics, particularly on the left side
What is a limitation of using enlarged ventricles to support a SZ diagnosis ?
Not all studies have found a consistent link between enlarged ventricles and SZ
