biological explanation for Sz

Question 1

what did Chloropromazine suggests of Sz

Answer 1

when people of Sz took the meds, postitive symptoms subsided but left them with tremors found in Parkinson’s disease which is known for a lack of dopamine.
this suggests that positive symptom and high levels of dopamine.

Question 2

what are reasons for high levels if dopamine for Sz

Answer 2

• lots of receptors which accept dopamine
• too little enzymes breaking down the dopamine.

Question 3

what did Davis et al say was the reason for positive and negative symptoms

Answer 3

• positive symptoms were due to an excess of dopamine in the mesolimbic pathway
• negative symptoms were due to lack of dopamine in the mesocortical pathway.

Question 4

what does Clozapine further suggest that affects symptoms

Answer 4

Clozapine blocks both dopamine and serotonin receptor sites. this reduced both negative and positive symptoms associated with Sz, showing that negative symptoms were due to irregular serotonergic activity.

Question 5

what are some strengths of the dopamine Hypothesis

Answer 5

• that cocaine use induced the effects of sz, as cocaine increases the levels of Dopamine the synaptic gap this suggests sz had to do with dopamine
• Tenn gave 9 amphetamines(mimic dopamine) to rates over 3 weeks, they started to show symptoms of Sz such as social withdrawal.

Question 6

what are some weaknesses of the dopamine hypothesis

Answer 6

• the drug apomorphine which is a dopamine agonist did not induce Sz symptoms, suggesting that dopamine levels are not the reason for Sz symptoms
• there may need to be further explanation. for example, second gen immigrants are more likely to be diagnosed with Sz.

Question 7

what was the heritability of Sz and how found this

Answer 7

79% and was found by Hilker et al.

Question 8

how does the COMT gene lead to Sz

Answer 8

COMT gene provides information for the instructions of enzymes to break down neurotransmitters. this poor regulation leads to Sz symptoms

Question 9

How dos the DISC1 gene lead to Sz

Answer 9

people with abnormality to the DISC1 gene are 1.4 times more likely to get Sz. this is because this creates GABA which regulates other neurotransmitters.

Question 10

what is the diathesis stress model

Answer 10

genes create a vulnerability to Sz rather than cause, conditions in the environment trigger these vulnerabilities.

Question 11

strengths of the genetic explanation for Sz

Answer 11

• Gottesman and shield showed that there is a relation between genetic similarity and people have Sz.
• Dahoun found that the DISC1 gene has an association with dopamine regulation which is a key factor in Sz

Question 12

weaknesses of the genetic explanation for Sz

Answer 12

although Gottesman and shield found a genetic similarities these are far form 100% with concordance rates being 42% for MZ and 9% for DZ, therefore Sz is only partly due to nature.