biological explanations for schizophrenia: ao1

Question 1

purpose of family studies

Answer 1

find individuals with schizophrenia and determine whether their biological relatives are similarly affected more often than none relatives

Question 2

who conducted a family study and when

Answer 2

gottesman 1991

Question 3

gottesman 1991 procedure

Answer 3

meta analysis of 40 studies

Question 4

what did gottesman 1991 find

Answer 4

children with 2 schiz parents had a concoordance rate of 46% and those with 1 schiz parent had 13% and siblings had 9%

Question 5

purpose of twin studies

Answer 5

if mz twins are more concoordant than dz twins it suggests similarity due to genes
looks at relative contribution of genes and environment

Question 6

who and when conducted twin study

Answer 6

joseph 2004

Question 7

joseph 2004 procedure

Answer 7

meta analysis of twin studies conducted before 2001

Question 8

joseph 2004 findings

Answer 8

combined concordance rate of 40% for mz
7% for dz

Question 9

what are adoption studies

Answer 9

studies of genetically related individuals who have been reared seperately

Question 10

who and when did adoption study

Answer 10

tienari et al 2000

Question 11

tienari et al - what did he find

Answer 11

found that 164 adoptees w schiz mothers 6.7% also recieved a diagnosis compared to just 2% of the 197 control adoptees

Question 12

what are neural correlates of schizophrenia

Answer 12

paterns of structure or activity in the brain that occur in conjunction with an expirence and may be implicated in the origins of that expirence

Question 13

main neural correlate

Answer 13

dopamine hypotheisis

Question 14

describe the original dopamine hypothesis

Answer 14

an excess of neurotransmitter dopamine in certain reigons of the brain is associated with the positive symptoms of schizophrenia

Question 15

revised Dopamine hypothesis

Answer 15

Brain of schiz patients produced more dopamine than that of normal
excess of dopamine in the mesolimbic pathway (reward pathway) - can lead to positive symptoms
or
deficit of dopamine in areas of the prefrontal cortex - areas responsible for thinking, decision making etc leading to negative symptoms (cog impairment, avolition)

Question 16

Evidence for dopamine hypothesis

Answer 16

PET SCANS
studies w drugs
Post mortem evidence

Question 17

Explain dopamine hypothesis

Answer 17

Dopamine receptors fire too often and or the dopamine fails to bind to the post synaptic membrane causing too much activity in the synaptic cleft

Question 18

Role of recreational drugs on dopamine

Answer 18

Ampthetamines and cannabis leads to increase in dopamine levels
Large quantities can lead to delusions and hallucinations in non sufferers
If drugs are given to schizophrenic patients their symptoms get worse

Question 19

Evidence of dopamine from Parkinson’s disease

Answer 19

Ppl w Parkinson’s have low dopamine levels
L DOPA drug raises dopamine activity
Ppl w Parkinson’s dev schiz symptoms if they take too much

Question 20

Explain phenothiazine role in providing evidence for dopamines role in schiz

Answer 20

A drug which reduce dopamine levels
Provide considerable relief from the positive symptoms of schiz

Question 21

What did falkai
et all find 1988

Answer 21

Found that people w schiz have a abnormally large amounts of dopamine receptors
Concluded that dopamine production is abnormal in all schizophrenics

Question 22

PET scan evidence

Answer 22

Gjedde and wong 1987
There are twice as many dopamine receptors in schizophrenics compared to controls
Farde et al 1990
There is no difference in the number of dopamine receptors between schizophrenics and controls

Question 23

Cause and effect issue in dopamine hypothesis

Answer 23

Faulty chem causing schiz or other way round
Drugs may influence other systems that impact schiz so can’t be 100% sure about their effects

Question 24

Updated versions of dopamine hypothesis

Answer 24

Kenneth Davi’s 1991
Proposed the addition Abnormally low levels of dopamine in the brains cortex

Question 25

Abonormally low levels of dopamine in the prefrontal cortex…

Answer 25

Responsible for thinking
Could explain cognitive problems (-ve symtptoms of schiz)

Question 26

Via updated hypothesis what makes people more sensitive to higher or Loewe levels of dopamine

Answer 26

Both genetic versions and Earky experiences of stress both psychological and physical make people more sensitive to high or now levels of dopamine

Question 27

Via updated hypothesis what makes people more sensitive to higher or Loewe levels of dopamine

Answer 27

Both genetic versions and Earky experiences of stress both psychological and physical make people more sensitive to high or now levels of dopamine

Question 28

Brain structure in schiz ev

Answer 28

Brain struc in patient w schiz different to a non sufferer

Question 29

What is a neural correlate

Answer 29

Measurements of structure or function

Question 30

Neural correlates of negative symptoms

Answer 30

Avolition - loss of motivation
Ventral striatum is believed to be involved in the anticipation of reward which links to motivation
Abnormalities of the ventral striatum is thought to to be involved in the development of avolition

Question 31

Who did evidence supporting ventral striatum

Answer 31

Juckel 2006
Measured activity in this part of the brain in shchiz and found lower levels of activist compared to that of the control group
The found a negative correlation between activity levels in ventral sti and severity of overall negative sympt9ms in schiz

Question 32

Neural correlate of positive symptoms

Answer 32

Allen 2007
Scanned brains of patients w auditory hallucinations and compared them to a control group whilst they identied their own speech from others off of a recording
Found lower levels of activity in the superior temporal gyrus and anterior cingulate gyrus in the hallucinations group and this group also made more errors
There is a neural correlate of auditory hallucinations in these 2 parts of Thor brain

Question 33

Schiz Brian struc

Answer 33

Patients have less brain tissue
Stdhues have shows enlargement of cerebral ventricles 15% larger in some but not all people w schiz

Post motortem studies have shown changes in the amount and distribution of brain cells in some people with schizophrenia

Question 34

Ev for schiz brain structure

Answer 34

Wood et al
79 males who were considered high risk schiz compared to 49 healthy males
They looked at the size of the hippocampus it was slightly smaller in schiz patients