schizophrenia: biological explanations

Question 1

explain how schizophrenia runs in families

Answer 1

there is a strong relationship between the degree of genetic similarity and shared risk of schizophrenia. shown in gottessman’s
large scale family study.

Question 2

explain candidate genes in schizophrenia

Answer 2

schizophrenia is polygenic because a number of genes each appear to confer a small increased risk of schizophrenia

Question 3

the risk of developing schizophrenia among individuals who have family members is ——- than it is for those who do not

Answer 3

higher

Question 4

how is schizophrenia aetiologically heterogeneous ?

Answer 4

different combinations of factors can lead to the condition

Question 5

example Ripke et al 2014

Answer 5

previous data from genome wide studies.
the genetic makeup of 37,000 people diagnosed with schizophrenia was compared to 113,000 controls , 108 genetic variations were associated with increased risk of schizophrenia.

Question 6

explain neurotransmitter

Answer 6

the brains chemical messengers appear to work differently in the brain with schizophrenia

Question 7

explain hyperdopaminergia in subcortex

Answer 7

possible role of high levels or activity of dopamine in the subcortex

Question 8

what is the name for high levels of dopamine

Answer 8

hyperdopaminergia in the subcortex

Question 9

how can poverty of speech be explained through high levels of dopamine

Answer 9

excess of dopamine receptors in brocas area which is responsible for speech production may be associated poverty of speech

Question 10

explain hypodopaminergia in the cortex

Answer 10

low levels of dopamine in the prefrontal cortex which is responsible for thinking and decision making
leading to negeative symptoms of schizophrenia

Question 11

what is the name for low levels of dopamine ?

Answer 11

hypodopaminergia in the cortex

Question 12

what are neural correlates ?

Answer 12

measurements of the structure or function of the brain that correlates with an experience

Question 13

explain neural correlate of negative symptoms (loss of motivation)

Answer 13

motivation - anticipation of a reward
ventral striatum involved in this anticipation
abnormal activity levels in ventral striatum may lead to avolition

Question 14

explain jucket et als research

Answer 14

measured activity levels in the ventral striatum in schizophrenia and found lower levels than controls.

negative correlation between ventral striatum and severity of overall negative symptoms

Question 15

explain neural correlates of positive symptoms ?

Answer 15

lower activation levels in the superior temporal gyrus and anterior cingulate gyrus leads to positive symptoms such as hallucinations

Question 16

explain allen et als research

Answer 16

scanned the brain of people experiencing hallucinations

compared to control group
whilst identified if pre- recorded speech was theirs or others

lower activation levels in the the superior temporal gyrus and anterior cingulate gyrus.
also made more errors than control

Question 17

strength of genetic explanation of schizophrenia

support for genetic vulnerability runs in families

Answer 17

support for genetic vulnerability runs in families

in gottessman’s
large scale family study there is a strong relationship between the genetic similarity and shared risk of schizophrenia
highest in identical twins (most similar)
this shows that some genetic factors do make people more vulnerable

Question 18

strength genetic explanation of schizophrenia (adoption study)

Answer 18

children of people with schizophrenia heightened risk of schizophrenia

tienari et al
164 adoptees - biological mother with schizophrenia , 6.7% diagnosed
compared to 2% of the 197 control adoptees born to non schizophrenic mothers

shows a genetic liability to schizophrenia

Question 19

strength of dopamine hypothesis

Answer 19

evidence for abnormal dopamine functioning
dopamine in schizophrenia

agonists like amphetamine increase levels of dopamine
produce symptoms in non sufferers

curran et al

supports hyperopaminergia
high levels of dopamine lead to schizophrenia

Question 20

what is a strength of dopamine hypothesis (radioactive labelling)

Answer 20

radioactive labelling studies have show that dopamine is very prominent in schizophrenia

lindstroem et al

chemicals that are needed to produce dopamine are taken up faster in the brains of schizophrenic people

abnormal levels of dopamine is a likely explanation

Question 21

what is a strength of dopamine hypothesis (radioactive labelling)

Answer 21

radioactive labelling studies have show that dopamine is very prominent in schizophrenia

lindstroem et al

chemicals that are needed to produce dopamine are taken up faster in the brains of schizophrenic people

abnormal levels of dopamine is a likely explanation

Question 22

what is limitation of dopamine hypothesis (other neurotransmitters)

Answer 22

dopamine doesn’t
supply full explanation
ripkes study
some genes code for other neurotransmitters

effective drugs such as clozapine contain serotonin and dopamine

dopamine not of sole importance in schizophrenia

Question 23

what is a limitation of neural correlates (may not be cause)

Answer 23

there may another explanation for correlation of activity ventral striatum + negative symptoms

negative symptoms themselves causing less info passed

another factor present hat affects activity or striatum

neural correlates tell us relatively little
may not be accurate