Biological explanations of SZ

Question 1

Name the three explanations of SZ

Answer 1

1. The genetic basis
2. The dopamine hypothesis (DH)
3. Neural correlates

Question 2

Name the three features in the genetic basis which is a biological explanation of SZ

Answer 2

1. Ss runs in families -Identical twins evidence suggesting there is a genetic predisposition of SZ
2. Adoption studies used to show how environment and genetic factors are separated 11/164 were also diagnosed with SZ where all 164 had biological mothers with SZ- genetic liability of sz has been confirmed
3. Candidate genes- specific role in our genetic makeup and sz is polygenic (108 genes) - little predictive ability due to the number of genes involved
   genes that control dopamine increases the risk of SZ development due to it being a part of the 108 genes

Question 3

Explain 3 important factors for Sz running in families

Answer 3

1. Shows that there’s a genetic predisposition for Sz
2. Identical twins studies have shown there’s a 48% concordance rate,shows that genetics do play a role
3. The closer the relatedness to the Sz person the higher the risk of your predisposition

Question 4

Dopamine hypothesis
- What does dopamine regulate
- where is dopamine active
- what symptoms occur when there’s an excess of dop
- Reason why excess amounts of dopamine occurs

Answer 4

1. Dopamine regulates attention
2. Active in the Limbic system
3. • An excess of dopamine leads to pos symp of SZ
   • Abnormally high levels of d2 (squared) receptors on receiving neuron, leads to more bindings of receptors, so more neurons are fired

Question 5

Examples and meaning of Positive Symptoms of SZ

Answer 5

Delusions
Disorganised speech- due to abnormal thought processing
Grossly disorganised/ Catatonic behaviour- inability to finish a task

Question 6

Dopamine hypothesis

Explain how use of recreational drugs supports DH

1. Name a dopamine antagonist
2. What do normal people experience when taking these drugs
3. Use of anti-psychotic drugs- what do they do to dopamine in the brain, what is elimated, what i blocked

Answer 6

1. Amphetamine is the antagonist= stimulate nerve cells with dopamine –> flooding of synapses
2. taking these drugs makes normal people experience symptoms of SZ
3. Patients taking Anti-psychotic drugs get their symptoms eliminated due to blocking of the activity of dopamine in brain but reducing neural pathway activity

Question 7

Explain what the Revised hypothesis suggests

Answer 7

Revised hypothesis suggests neg symp arise when there’s a deficit of dopamine and serotonin

Question 8

What are the 3 things to mention in ao1 for neural correlates

Answer 8

1. Measures structure/function of the brain- how this correlates to an experience
   - use of MRI and PET scans
2. Contrasts of Neural activity in Non-SZ and patients with SZ
   - SZ have deficits in PFC
   - Deficits in nerve connections –> impairment of working memory
3. SZ patients with neg symptoms have larger ventricles (cavities with fluid) due to brain not fully developing unlike non SZ people

Question 9

AO3
Explain how research into Mz twins and what CR was found, and whether this is evidence to support the biological explanations

Answer 9

Research- MZ (identical) twins- supports biol expl but shows it isn’t conclusive
Findings: CR of 48% in MZ twins - shows there are other factors to consider because the CR would be 100% if it was all biological
=Biologically reduction

Question 10

AO3
Explain how the dopamine hypothesis is supported by successful treatments of antipsychotic drugs

Answer 10

The dopamine hypothesis= supported by successful antipsychotic drug treatment
Proven to balance out levels of dopamine which reduces positive symp, by blocking the dopamine receptors
Meta analysis evidence- 200 studies= show drug effectiveness Demonstrates how influential dopamine is, supporting bio expl

Question 11

AO3
Explain challenges to DH that led to Revised DH
Mention symptoms of SZ

Answer 11

Research found that Antipsychotic drugs= 1/3 patients pos symp are not prevented- not effective
pos symp remain present even when dopamine levels are balanced out
Therefore, Revised DH has improved drug treatment, using atypical AP D, as it balances dopamine and serotonin, which reduces pos AND neg symptoms
Shows DH didn’t address other neurotransmitter systems e.g. levels of serotonin

Question 12

AO3
Explain the strength of neural correlates - relate to scientific use of evidence and affects of early detection of SZ

Answer 12

Neural correlates of SZ evidence is scientific which makes it reliable due to the use of brain scanning techniques.
Longitudinal research shows how beneficial early detection of SZ is, because diagnosing SZ from correlating symptoms to abnormalities in the brain has led to early treatments which results in later development stages of SZ being prevented