Biological Explanation to Schizophrenia

Question 1

What is the genetic hypothesis?

Answer 1

The more closely the family member is related to the Sz, the greater their chance of developing the disorder

Question 2

Gottesman et al 1991

Answer 2

Family study that supported evidence for Sz genetic basis
Both parents- 46%
One parent- 16%
Sibling- 8%
Grandparent- 5%

Question 3

What is the probability of a person in the population having Sz?

Answer 3

1%

Question 4

Define polygenic?

Answer 4

Sz requires a number of factors and genes to increase the risk of inheriting Sz

Question 5

Define aetiologically heterogeneous?

Answer 5

One group of genes may cause Sz in one person but a different group of genes may cause the disorder in the other

Question 6

Ripke et al 2014

Answer 6

Carried out a large study combining all previous data from genome wide studies of Sz. 37,000 patients were compared to 113000 controls - there was 108 separate genetic variations that were associated with the risk of Sz including the neurotransmitter dopamine

Question 7

What is the dopamine hypothesis?

Answer 7

Dopamine is an important part in the functioning of several brain systems that may be implicated in Sz. Excess dopamine receptors in the Broca Area may be associated with speech poverty and the experience of auditory hallucinations

Question 8

Goldman 2004-

Answer 8

Identified the role of low levels of dopamine in the prefrontal cortex which is responsible for thinking and decision making in negative symptoms of Sz- low levels affect Sz too

Question 9

What are the neural correlates of negative thinking?

Answer 9

Avolution involves the loss of motivation- which involves the anticipation of rewards (which occurs in the ventral striatum) - therefore this area may be involved in the symptom

Question 10

Juckel et al 2006-

Answer 10

Measured neural activity in the VS in Sz and found lower levels of activity than those observed in control

Question 11

What are the neural correlations of positive symptoms?

Answer 11

Allen et al scanned the brains of patients experiencing auditory hallucinations and compared them to the control group whilst they identified pre-recorded speech as theirs others. Lower activation levels in the superior temporal gyrus were found in SZ patients.

Question 12

Evaluation of concordance rates in Gottesman study?

Answer 12

Concordance rates are not 100% so therefore suggest other influential factors
As concordance rates correlate with genetic relatedness- supports idea of environmental factors as people in families are more likely to spend more time together

Question 13

What is the problem with a nature alone theory?

Answer 13

It would be considered highly reductionist and deterministic

Question 14

Methodological issue with family studies?

Answer 14

Sample tends to be small so the population validity therefore may be small- can you generalise the findings

Question 15

Evidence supporting the dopamine hypothesis?

Answer 15

Amphetamines that increase the level of dopamine in a person make Sz worse and can produce symptoms of Sz in non sufferers
Anti-psychotic drugs reduce dopamine and reduce symptoms of Sz

Question 16

Lindstroem 1999-

Answer 16

Looked at radio active studies and found that the chemicals needed to produce dopamine are taken up faster in Sz sufferers suggesting that they produce more dopamine

Question 17

What is important about the role of mutation?

Answer 17

Suggests that Sz can take place in families with no history of the disorder- links to mutation of the paternal sperm cell which could be caused by a viral infection

Question 18

Brown et al 2002

Answer 18

A positive correlation between paternal age and risk of Sz increasing from 0.7% in fathers under 25 and 2% chance in fathers over 50