biological explanations Flashcards
what do neural correlations explain?
States that abnormal brain structure causes SZ
For example people with SZ have larger ventricles in the brain than normal and a smaller frontal cortex
what is the role of dopamine in explaining schizophrenia ?
Too much dopamine has been linked to SZ. The neurons that transmit dopamine fire too often and transmit too many messagesThe lowering of the dopamine helps to remove symptoms of SZ.
what is hyperdopaminergia?
High activity of dopamine in the subcortex.
Excess amount of dopamine receptors in broca’s area may be associated with speech poverty/auditory hallucinations
what is Hypodopaminergia?
Abnormal dopamine system in the brain’s cortex e.g. Low levels of dopamine associated with negative
study into neural correlations:
allen et al
scanned the brains of patients experiencing auditory hallucinations and compared them to a control group whilst they identified pre-recorded speech as theirs or others.Lower levels of activity in the superior temporal gyrus and anterior cingulate gyrus were found in the hallucination group that made more errors.
evalutation for neural correlates hypothesis:
strength
increase of dopamine
curran et al found that the increase in dopamine mimics the symptoms of SZ and antipsychotic drugs used to reduce dopamine also reduce the intensity of the symptoms associated with SZ.Also candidate genes act on the production of dopamine or dopamine receptors.
evaluation : weakness
correlation causation
there are a number of neural correlates of schizophrenia symptoms.It may be that unusual activity in those regions cause the symptom or the other way around.
genetic basis:
family studies
Schizophrenia runs in families however this is weak evidence of a genetic link because families share environments as well as genes.
what family study did Gottesman conduct?
a large-scale family study and found that the more the genetic similarity, the higher the chance of developing SZ. For example, identical twins that share 100% of their genes have a 48% risk of developing SZ while fraternal twins who share 50% of their genes have a 17% risk.
explain candidate genes as a biological expanantion?
Different studies have identified candidate genes and therefore different combinations of factors can lead to SZ
Individual genes are associated with the risk of inheritance
what did Ripke study under biological explanations?
conducted a genome wide study combining all previous data of SZ. The genetic makeup of 37000 patients was compared to 113000 controls; 108 separate variations were associated with increased risk of SZ. Genes associated with increased risk included those coding for the functioning for a number of neurotransmitters including dopamine.
evaluation: strength
gottesman and tienari et al
Gottesman family studies clearly shows that genetic similarity and shared risk of SZ are closely related. Tienari et al. Adoption studies showed that children of people with schizophrenia are still at a heightened risk of developing SZ even when adopted into a home without a history of SZ.
what does gottesman and tienari et al studies show ?
This shows that there are genetic factors that play a role in making some people more vulnerable to developing SZ than others. This doesn’t mean that developing SZ is entirely genetic as there are environmental factors that have a role however we can still see that genetic vulnerability is important.
evaluation: limitation
environmental risk factors
Biological risk factors include complications in childbirth and smoking THC rich cannabis in the teenage years. Psychological factors include childhood trauma and 67% of those with SZ reported at least 1 childhood trauma.
Therefore this shows that genes alone cant provide a complete explanation for SZ.
