2. Biological Explanations of Schizophrenia Flashcards
name the two biological explanations for schizophrenia
- Genetic
- Dopamine Hypothesis
- Neural Correlates
what studies have helped determine whether schizophrenia is caused by genetics
twin studies between monozygotic and fraternal twins
outline Gottesmans findings based off twin studies developing schizophrenia
- discovered that MZ twins have a 48% chance of developing it
- whereas DZ twins have a 17% risk, suggesting there is genetic relativeness
what genes did Benzol discover and what did they mean?
COMT, DRD4, AKT1
found these genes are associated with excess dopamine in specififc D2 receptors, which leads to the positive symptoms of schizophrenia
what did research from Miyakawa conclude about schizophrenia
- that DNA from families with schizophrenia were more likely to have a defective gene which means the immune system is not regulated effectively
what did Kendler show about schizophrenia
that first degree relatives are more likely to develop schizophrenia
name a strength of the genetic explanation
that there is evidence supporting it, However, genetics are only responsible otherwise the concordance rate would be 100%
name the limitations of the genetic explanation
- the family and twin studies are retrospective, meaning there are methodological problems, which could cause demand characteristics
- there is a nature/nurture debate as concordance rates were not 100% which means that there will be other influences despite genetics
- it is biologically reductionist, and does not explain a causality between the genes and the development of schizophrenia in some cases, just that genes seem to increase the likelihood and that a correlation is present
what is the original dopamine hypothesis regarding developing schizophrenia
- states that excess amounts of dopamine, leads to more frequent action potentials which means too many messages are being transmitted
- this leads to positive symptoms
what is the second dopamine hypothesis regarding the development of schizophrenia
- that it is the dopamine receptors which are responsible
- more receptors lead to more action potentials
- this has been supported by autopsies as people have been discovered to have excess dopamine receptors and dopamine
what are the limitations of the dopamine hypothesises
- that it is not clear what the cause and effect relationship is as it is unclear if excess dopamine causes schizophrenia or if schizophrenia causes excess dopamine
- biologically deterministic does not take into account other correlations when developing schizophrenia
what is the strength of the dopamine hypothesis
Owen et al showed that those who had schizophrenia had excess dopamine receptors and excess dopamine within their cells after their death and during autopsy, which suggests a correlation
define neural correlates
structure or patterns of activity that happens in the brain in link withy schizophrenia
what do people with schizophrenia have in their brain compared to normal humans
they have larger ventricles, which means their brain is 15% bigger than usual and is lighter as the ventricles remove waste and supply nutrients
list strengths of the neural explanation of schizophrenia
- the research into ventricles has high reliability due to the fact it was done in a high controlled environment
- machines such as MRI and PET scans are conducted on the brain which means that it has high validity and likelihood of achieving the same results if repeated, especially as the hippocampus is scanned
