biological explanations of SZ✅

Question 1

what are the 3 explanations?

Answer 1

1- genetic basis of SZ

2- The dopamine hypothesis

3- neural correlates of SZ

Question 2

1️⃣ genetic basis of SZ:

what does SZ run in?

whats there a strong relationship between?

what are candidate genes?

Answer 2

• families
• the degree of genetic similarity and the shared possibility of SZ
• individual genes associated with the risk of inheritance

Question 3

1️⃣genetic basis:

how does SZ appear to be polygenic?

what does aetiologically heterogeneous mean?

what did ripke et al conduct his meta analysis about

Answer 3

• bc the number of genes each appear to confer an increased risk of sz …. diff factors combined
• diff factors can lead to the condition
• looked at the genetic makeup of 37,000 patients in total and found 108 separate genetic variations adsosoated with Sz (including dopamine)

Question 4

2️⃣the dopamine hypothesis:

what does dopamine have do with sz?

what did there hypothesis state?

what does hyperdopaminergia mean? what does this lead to? what kind of symptoms?

what does hypodopmineergia mean? what kind of symptoms?

Answer 4

• its believed to be involved and its important in the functioning of brain systems Implicated with sz

sz ppl suffered from an excessive amount of dopamine causing neurons that use dopamine to fire too often and transmit too many messages.

• hyper = too much dopamine …. leads to delusions and hallucinations … positive symptoms
• hypo = too little dopamine … negative symptoms (speech poverty)

Question 5

3️⃣ neural correlates of sz

what is it?

Answer 5

• measurement of the the structure and function of the brain that correlates with positive and negative symptoms

Question 6

3️⃣ neural correlates - POSITIVE SYMPTOMS:

what did Allen et al study?

what was there task? ( identifying voices)

where did they find lower activity (gyrus)

Answer 6

• the brains of patients experiencing auditory hallucinations and compared to a control group
• identifying pre recorded voices of them selves or someone else
• in the superior temporal gyrus + anterior cingulate gyrus … in those experiencing hallucinations

Question 7

3️⃣ neural correlates - NEGITIVE SYMPTOMS:

What does avolition involve?

what area of the brain is associated with there anticipation of a reward?

what did juckel et al measure?

what did they find a negative correlation between?

Answer 7

• the loss of motivation involving the anticipation of a reward
• the ventral striatum
• activity in the VS and lower levels in patents with sz compared to controls
• activity in this area and the severity of the symptoms

Question 8

Ao3:

❌ 2weakness

✅ strength

Answer 8

❌ neuro. exp. - is that it is biologically deterministic. The reason for this is because if the individual does have large ventricles then does it really mean that they will develop schizophrenia? This suggests that the dopamine hypothesis does not account for freewill.

❌ genetic explanation of schizophrenia is that there are methodological problems. Family, twin and adoption studies must be considered cautiously because they are retrospective, and diagnosis may be biased by knowledge that other family members who may have been diagnosed. This suggests that there may be problems of demand characteristics.

✅ role of mutation … sz can take place in the absence of a family history of the disorder. One explanation for this is mutation in parental DNA, for example, in paternal sperm cells. This can be caused by radiation, poison or viral infection. Evidence for the role of mutation comes from a study showing a positive correlation between paternal age (associated with increased sperm mutation) and risk of Sz, increasing from around 0.7% with fathers under 25 to over 2% in fathers over 50. This does suggest a biological cause for schizophrenia.
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