Biological explanations for Schizophrenia

Question 1

family studies - what did Kendler find

Answer 1

if a first degree relative has Sz you are 18 times more likely to develop it than the general population

Question 2

family studies - what are the concordance rates for when 2 parents, 1 parents and a sibling have Sz, and who found them

Answer 2

2 parents - 46%
1 parents - 13%
sibiling - 9%, Gottesman

Question 3

twin studies - what concordance rates did Joseph find

Answer 3

Mz twins - 40.4%

Dz twins - 7.4%

Question 4

twin studies - what have more recent methodologically sound studies found

Answer 4

lower concordance rates than Joseph but Mz still have a higher concordance rate than Dz twins

Question 5

adoption studies - how many adoptees did Tienari study (Sz and control group), how many received diagnosis of Sz (Sz and control group)

Answer 5

164 Sz adoptees, 197 control group

6.7% of Sz adoptees, 2% of control group

Question 6

why do all concordance rates with regards to genetic factors support the biological explanation

Answer 6

they are all higher than 1% which is the general population risk of development

Question 7

what does the dopamine hypothesis state

Answer 7

messages sent from neurones that transmit dopamine fire too easily/too often

Question 8

what is an excess of dopamine in the brain associated with

Answer 8

positive symptoms of Sz

Question 9

schizophrenics are thought to have abnormally _ numbers of _ receptors on receiving _ resulting in more _ binding and so more neurones _

Answer 9

schizophrenics are thought to have abnormally high numbers of D2 receptors on receiving post-synaptic neurones, resulting in more dopamine binding and so more neurones firing

Question 10

what 2 drugs increase dopamine levels

Answer 10

amphetamine and L-dopa

Question 11

what is amphetamine and what does it do

Answer 11

dopamine agonist, stimulates nerve cells containing dopamine causing a flood of dopamine in the synapse

Question 12

what is L-dopa used for

Answer 12

Parkinson’s patients need it to increase dopamine levels, sometimes leads to the development of Sz symptoms

Question 13

what drugs decreases dopamine levels and explain

Answer 13

antipsychotics - block dopamine activity in the brain and eliminate Sz symptoms

Question 14

who revised the dopamine hypothesis

Answer 14

Davis and Kahn

Question 15

what is the revised dopamine hypothesis

Answer 15

positive symptoms are caused by an excess of dopamine in the subcortical areas/mesolimbic pathway of the brain, negative symptoms are caused by a deficit of dopamine in the prefrontal cortex

Question 16

_ et al used _ scans to assess dopamine in normal p’s and Sz p’s. he found _ levels of dopamine in the _ _ _ of Sz compared to normal p’s

Answer 16

Patel et al used PET scans to assess dopamine in normal p’s and Sz p’s. he found lower levels of dopamine in the dorsolateral prefrontal cortex of Sz compared to normal p’s

Question 17

_ and _ depleted dopamine in _. they found _ _ which was reversible using _, an _ antipsychotic

Answer 17

Wang and Deutch depleted dopamine in rats. they found cognitive impairment which was reversible using olanzapine, an atypical antipsychotic

Question 18

name 3 evaluation points for genetic factors

Answer 18

• common rearing patterns may explain family similarities
• Mz twins encounter more similar environments than Dz twins
• adoptees may be selectively placed

Question 19

genetic factors evaluation- what did Joseph find with regards to adoptees being selectively placed

Answer 19

adoptive families in Denmark and the US are informed of the child’s genetic background, so perhaps families who adopt children with Sz in their background have an environment which may trigger the Sz, e.g. family dysfunction

Question 20

genetic factors evaluation- common rearing patterns may explain family similarities…

Answer 20

negative emotional climates causes stress which triggers the onset of Sz. maybe the environment is the biggest factor in the onset, not heredity, there is a lot of evidence for the environment playing a role e.g. high EE makes p’s 4 times more likely to relapse

Question 21

genetic factors evaluation- how do Mz twins encounter more similar environments

Answer 21

treated more equally and experience identity confusion

Question 22

dop hyp evaluation - evidence from treatment came from _ meta-analysis of _ studies analysing _ and found…

Answer 22

Leucht et al, meta-analysis of 212 studies analysing the effectiveness of a placebo vs antipsychotic drugs. found drugs were more effective at treating pos and neg symptoms achieved through the normalisation of dopamine levels. if treatment works this proves the theory is correct

Question 23

dop hyp evaluation - inconclusive supporting evidence from _ states that _ affect more _ than just dopamine. also other factors influencing an _ of dopamine aren’t considered such as _ and _

Answer 23

inconclusive supporting evidence from Moncrieff states that amphetamines affect more neurotransmitters than just dopamine. also other factors influencing an increase of dopamine aren’t considered such as smoking and stress

Question 24

dop hyp evaluation - Noll claims there is _ _ _ for the revised+dopamine hypothesis. he argues antipsychotics don’t reduce symptoms in _ of people. _ symptoms can occur with _ dopamine levels so _ the _ receptors has _ effect, _ the hypothesis

Answer 24

Noll claims there is inconclusive supporting evidence for the revised+dopamine hypothesis. he argues antipsychotics don’t reduce symptoms in 1/3 of people. positive symptoms can occur with normal dopamine levels so blocking the D2 receptors has no effect, rejecting the hypothesis