Biological Explanations

Question 1

Genetic Factors

Answer 1

the closer the genetic relationship, the greater the probability of the disorder being expressed

MZ Twins- 100% DNA
DZ Twins- 50% DNA
- If there’s a higher rate (concordance) for MZ twins, greater support for the role of genetics

Rosenthal (Twin Studies)
- set of female quadruplets
- all developed SZ although the onset and symptoms were different- could be due to troubled upbringing
- suggests a strong heritiable component

Question 2

Neural Correlates

Answer 2

Specific patterns of coritical activity or neural structures which coincide with specific psychological symptoms, and so are assumed to contribute towards those symptoms
- people with SZ have abnormally large ventricles in the brain
- filled with fluid cavities in the brain that supply nutrients and remove waste

SZ brains are lighter than normal
Ventricles are 15% bigger than normal- Torrey (2002)

Question 3

Dopamine Hypothesis

Answer 3

SZ results from an inbalance of dopamine in the brain. Small specialised receptors recieve them and neurotransmitters has differnt types

Dopamine=a neurotransmitter associated with the reward system in our brain and some areas of the brain that are important with speech and movement

Increased levels of dopamine= Hyperdopaminergia
Excess dopamine receptors= Speech Poverty

Decreased levels of dopamine= Hypodopaminergia
Low levels of dopamine in prefrontal cortex= Negative Symptoms

Question 4

A03- Biological Explanations
(Adoption Studies)

Answer 4

Pekka Tinari et al (2004)
- children of people with SZ still have heightened risk of SZ even if adopted with no history of it
- Biological Parents with SZ- 6.7%. No history-2%

Evidence from studies conducted at the molecular level showing that particular genetic variations significantly increase the risk of SZ
-this presents the idea that genetic factors make some people more vulnerable to developing SZ than others

However, this doesn’t suggest that the explanations of SZ are purely genetic- DETERMINISTIC

Question 5

A03- Biological Explanations
(Support for Dopamine Hypothesis)

Answer 5

Agonists- increased levels of dopamine, make SZ worse and can produce SZ-like (Amphetamines) symptoms in non-sufferers

Anti-Psychotics- decreased dopamine activity
- both drug studies suggest that dopamine has an important role in explaning and treating SZ

Issues and Debates
Too Deterministic- explains SZ soley on biological factors such as genes and the production of dopaminw
- does not take into consideration the environmental impacts of the development of SZ

Question 6

A03- Biological Explanations
(Correlation not causation)

Answer 6

The evidence on the relationship between SZ and dopamine levels is mostly correlational in nature

As a result, we don’t know whether the changed dopamine activity in schizophrenics occurs before or after onset of the disorder
i.e- a cause or effect of the illness