biological explanations and therapies

Question 1

genetic explanation

Answer 1

schizophrenia runs in families, inherited as genes from parents

Question 2

Gottesman

Answer 2

twin studies
- conducted a large scale family study
- MZ twins have 48% concordance rate than DZ twins, only 17%
- support bc MZ share 100% of genes and DZ only 50%

Question 3

candidate genes

Answer 3

believed to be associated with risk of inheritance of SZ
- believed to be polygenic (Ripke found 108 gene variations associated w SZ)

Question 4

Dopamine hypothesis

Answer 4

high dopamine activity leads to acute episodes and positive symptoms

Question 5

amphetamines

Answer 5

increase the amount of dopamine, so if small dose given to a SZC, symptoms worsen

Question 6

the role of dopamine

Answer 6

important in the functioning of several brain systems that may be implicated in the symptoms of SZ

Question 7

hyperdopaminergia (subcortex)

Answer 7

high levels/ activity of dopamine in the subcortex may be associated w positive symptoms such as auditory hallucinations
- bc Broca’s area (regulates speech)
- original version of dopamine hypothesis

Question 8

hypodopaminergia (cortex)

Answer 8

low levels of dopamine in prefrontal cortex may be associated w negative symptoms

Question 9

neural correlates

Answer 9

structure/ activity in the brain that occur along with an experience
- associated w positive & negative symptoms

Question 10

neural correlates of negative symptoms

Answer 10

avolition = loss of motivation
- motivation involves anticipation of reward
- ventral striatum involved w anticipation
- Juckel et al found lower levels of activity in VS in SZC’s than control
- pos correlation between Vs activity and negative symptoms

Question 11

neural correlates of positive symptoms

Answer 11

Allen et al found lower activation in superior temporal gyrus and anterior cingulate gyrus in SZ group
- they all experienced auditory hallucinations
- reduced activity in these 2 areas = neural correlate of auditory hallucinations

Question 12

supporting evaluation for biological explanations

Answer 12

research support for genetics
- Gottesman twin study
> CA, MZ twins usually treated as ‘twins’ rather than individuals and treated similar
- Tienari et al adoption study
- genetic factors make some ppl more vulnerable to developing SZ than others

Question 13

Tienari et al

Answer 13

long term study in Finland
- 124 adoptees w SZC biological mothers
- 147 socia-demographically matched control
- 9/124 became psychotic
- 2/147 became psychotic

Question 14

limiting evaluation for biological explanations

Answer 14

mixed evidence for dopamine hypothesis
- dopamine agonists (amphetamines) increase symptoms in SZC’s and can create SZ like symptoms in normal ppl
- antipsychotics reduce dopamine activity, used to treat SZ
- chemicals needed to produce dopamine are taken up faster in SZC’s brains, shows they create more dopamine
- but also evidence that dopamine is not the only hormone to be associated w SZ
- Ripke found genes that call for the production of other neurotransmitters
- shows dopamine is important but others exist too (eg. glutamate)

Question 15

drug therapy

Answer 15

most common treatment for SZ
- uses antipsychotics

Question 16

antipsychotics

Answer 16

• may be required in LR or SR
• some can take for a short time and stop w/o return of symptoms
• others need them for life or face recurrence

Question 17

typical antipsychotics

Answer 17

work as dopamine antagonists (chlorpromazine)
- block dopamine receptors in the synapses of the brain, reducing action of dopamine
- normalises neurotransmission in key areas, reducing symptoms like hallucinations
- initially dopamine levels increase but then production reduces

Question 18

atypical antipsychotics

Answer 18

minimise side effects, also addresses neg symptoms
- clozapine, can cause a blood condition so ppl who take it have regular blood tests
- binds to dopamine receptors like typical, but also serotonin and glutamate receptors
- helps improve mood, reduce depression and anxiety
- prescribed to suicidal ppl, 30-50% of SZC’s

Question 19

supporting evaluation for biological therapies

Answer 19

evidence for effectiveness
- Thornley et al, ppl on chlorpromazine had better overall functioning and reduced symptom severity
- Leucht et al, meta-analysis of 65 studies, 6000 ppt, all on antipsychotics, some taken off and given placebo
- withing 12m, 64% of placebo relapsed, only 27% of antipsychotics

Question 20

limiting evaluation for biological therapies

Answer 20

likelihood of side effects
- typical = dizziness, agitation, sleepiness…
- long-term use can = tardive dyskinesia
- most serious = neuroleptic malignant syndrome = high temp, delirium, coma
- atypical have fewer but still some like agranulocytosis