Genetic Exp of SZ + Gottesman and Sheild

Question 1

What is SZ

Answer 1

• MENTAL ILNESS which affects the **way you think **
• it affects 1/100 people
• usually developed early adulthood
• you can have positve and negative symptoms
• positive symptons are experiencing things that are not real such as hallucinations or delusions (unusual beliefs), disorganised thinking
• negative symptoms are often longer lasting than postive symtpoms and are due to lack of motivation and being withdrawn
• Males more likely to have poor development of disorder than women and can develop higher proportion of negative symptoms and have longer duration of the disorder

Question 2

How to diagnose SZ?

Answer 2

• when diagnosing SZ there are no blood test or scans to prove you have SZ
• so you can only be diagnosed by psychiatrists who will do a will psychiatric assessment by using a diagnostic manuals IDC and DSM

Question 3

What are Positive Symptoms?

Answer 3

add experience to patients
- Delusions
- Grandiose delusions = have remarkable qualities
- persecutory delusiosn = others are ‘out to get them’ leading to harm and manipulation
- hallucinations
- disorganised thinking/speech
- thought insertion = person thinks their own thoughts are put there by someone
- thought broadcasting = others can **hear their thoughts **

Question 4

What are negative symptoms?

Answer 4

Subtract from normal behaviour/normal functioning is not present
- loss of emotion,speech or motivation
- starts before postivive symptoms and years before SZ is diagnosed
- lack of energy/apathy
- social withdrawal
- flatness of emotions
- lack of pleasure in activies/life
- not looking after apearance + personal hygeine

Question 5

What are the assumptions of genes in SZ?

Answer 5

assume SZ is a heritable condition that pass down from generatiosn
- it it said 700+ genes are linked to SZ

genetic varaition causes SZ
- COMT gene provides instructions to break down dopamine
- if there’s variations within in COMPT it leads to poor regualtion of dopamine leading to excess of dopamine in prefrontal cortex
- DISC 1 gene is responsbile forregulation GABA which regulates dopmaine and glutamine in the limbic system
- if there is variations in DISC 1 there will be irregular neurostransmitter activity

Question 6

What is the Diathesis-stress model?

Answer 6

INHERITING A GENETIC VARITION of DISC1/COMT makes individual more vunerable to developing SZ rather than genetic variation directly cause SZ
- they have predisposition to SZ to more likely to develop SZ than someone without inheriting genetic variation
- these predispositions trigger likely of SZ from environmental factors e.g. trauma, stressful events, drug us

Question 7

How does Gottesman and Sheilds support the Diathesis-Stress Model?

Answer 7

Gottesman + Sheilds is an important twin study for explaning genetic explanations of SZ
- His results showed closer genetic relationship but MZ showed 75% concordance rate not 100% meaning that it’s not entirely caused by genetics but genetics predispose SZ to become more vunerable to trigger from environmental factors
- supports the interaction between **biological and environmental factors **

Question 8

What was the aim of Gottesman + Sheilds?

Answer 8

• Investigate weather SZ had a genetic basis by comparing the concordance rateof SZ in MZ and DZ twins

Question 9

What were the procedures for Gottesman + Sheild?

Answer 9

• They looked at records from psychiatric hospitals over 16 years history and 62 patients were identified and their twins were tracked down to participate
• to determine MZ and DZ they did finger print testing, blood testing and resemblance

PRIMARY DATA WAS COLLECTED
- questionnares and interviews with twins and parents
- tape recordings of verbal behaviour from semi-structured interviews
- personality test to measure* disordered thinkin **

SECONDARY DATA
- collected from hospital notes from the **psychiatric ward **

Question 10

What were the results for Gottesman and Sheild?

Answer 10

• there were 75% concordance rate for MZ twins of severe SZ
• were were 17% concordance rate for MZ twins of mild SZ
• there were 27% concordance rate for DZ twins of severe SZ
• there were 0% of DZ concordance rate for DZ twins of severe SZ

Question 11

What were the conclusions for Gottesman and Sheild?

Answer 11

• Showed the closer the genetic relationship the greater the likelihood that if one twins was diagnosed, the other would likely get the diagnosis
• MZ twins didn’t show 100% concoordance rate of severe SZ
• suggest its not all down to genetics, environmental factors trigger the predispose SZ
• supports the diathesis-stress model