Schizophrenia: Other Biological Explanation- Brain Structure

Question 1

Why do we look at brain structure as an explanation for the development of sz?

Answer 1

There is much evidence to suggest that brain structure is different in schizophrenia patients compared to a healthy person

Question 2

Areas of brain linked to sz

Answer 2

• enlarged ventricles
• PFC
• frontal lobes
• basal ganglia
• loss of grey matter

Question 3

Enlarged ventricles definition

Answer 3

• Centres of the brain that contain cerebrospinal fluid
• supply blood and oxygen to neurons
• fluid filled cavities that supply nutrients and remove waste.

Question 4

How do ventricles affected by sz?

Answer 4

• schizophrenics have enlarged ventricles.
• ventricles are on average about 15% bigger than normal
• usually due to underdevelopment in some areas or loss of brain cells that causes fluid to fill the empty space
• causes as thinning of the cerebral lining
• can also be caused by the death of brain tissue

Question 5

How can enlarged ventricles explain the symptoms of sz

Answer 5

• may result in the disruption of the limbic structures- such as the hippocampus-
• so may lead to paranoia or delusions.
• can also better explain negative symptoms- such as greater cognitive disturbances and poor responsiveness to drug therapy

Question 6

How can brain structure be affected?

Answer 6

• Factors during the womb, the birth process or after birth
• this can cause brain lesions- making an individual vulnerable to sz- as this will impact the development of the brain.
• this can also cause damage which may impair ability to grow.

Question 7

Ao3 study for enlarged ventricles support

Answer 7

Suddath et al can be used to support. He used MRI scans to obtain pictures of the brain structures of MZ twins, in which one was schizophrenic. Suddath found that the sz twin generally had enlarged ventricles- and the differences were so large that the twins could easily be identified from the brain images produced in 12/15 pairs. Therefore, this suggests that the enlarged ventricles can contribute towards the development of positive symptoms and explain the cause of sz.

Question 8

Explain how the basal ganglia can explain sz

Answer 8

• basal ganglia is linked to dopamine activity
• this is linked to the development of sz linked to cognitive dysfunction
• involves movement and thinking skills
• some studies have shown that it is larger in sz
• might affect movement of sz, who often have motor dysfunctions, such as cataleptic stupor

Question 9

What other areas can be linked to sz?

Answer 9

The frontal lobes, temporal lobes, hypothalamus, hippocampus can be found to have abnormal structural problems.

Question 10

Supporting evidence for other brain structures linking to sz?

Answer 10

Turner et al can be used as supporting evidence for brain structure leading to the development of sz. They examined MRI scans of brains from 2028 sz patients and 2540 healthy patients, and found that patients with sz tended to have smaller volume in brain regions that included the hippocampus, amygdala and thalamus than their healthy peers- supporting the idea that the brain structure can explain sz.

Question 11

Evaluate supporting research (T)

Answer 11

This study was the largest structural brain meta-analysis to date in schizophrenia, using primary data as well as secondary data. Researchers used standardised statistical measurements in highly controlled environments such as MRI scans this ensures that there is accurate reading readings of pre-frontal cortex, the hippocampus and the amygdala, increasing the internal validity of the results. Overall, research into brain structure affecting sz has high validity, increasing the scientific status of the explanation that brain structure is a cause of sz.

Question 12

Explain how damage to the frontal lobes can explain sz

Answer 12

• catatonia and speech poverty are common negative symptoms for those with sz and that suffer brain damage.
• brain imaging techniques have shown that low levels of activity in the frontal lobes is similar to those with frontal lobe damage.
• the PFC plays a role in behaviours such as speech, decision making, and willed actions. This can be disrupted in sz, possibly due to the reduction in grey matter.
• sz also have reduced metabolic rates in the PFC- may be one reason they suffer from delusions- they aren’t using the part of their brain which induces logical thinking
• disorganised thought patterns can be due to damage PFC

Question 13

How can the loss of grey matter explain sz?

Answer 13

• can explain cognitive dysfunctions such as poor working memory and processing language.
• reduction in the temporal and frontal regions leads to more severe symptoms

Question 14

How can damage to the PFC in the womb link to the onset of sz?

Answer 14

• damage to PFC is correlated with sz, and so any damage to area as a child would not be seen until it develops/fuly develops through adolescence whereby any damage would become prevalent
• explaining late onset of sz/not being present/prevalent in children

Question 15

How can the amygdala explain sz?

Answer 15

Smaller amygdala with lower activity= people with sz often show little, blunted emotion.

Question 16

Application of this theory

Answer 16

A strength of this theory is that it has positive applications- the insight could change how physicians use anti-psychotic drugs to treat sz, with the view that those with the disorder can lead productive lives- with he right balance of care, therefore by understanding the influence brain structure can have on sz is important for the future applications in level of care for patients.

Question 17

Criticism of the theory

Answer 17

It is highly reductionist. The theory states that sz is down to brain damage occurring biologically- therefore disregarding environmental factors that influence brain damage— such as TBI. It cannot also explain why those with damage to their PFC or amygdala do not develop sz. Sz likely arises from a complex interaction of brain structure, environmental triggers such as low social class and neurotransmitters. Therefore, the stress-diathesis model is a better explanation of sz development- there may be biological predispositions for sz such as enlarged ventricles or smaller volume amygdalas, but sz will only occur when there is environmental triggers to cause these symptoms to appear.

Question 18

Overall evaluation of the research

Answer 18

• low validity
• cannot establish cause and effect
• this is because research is correlational
• brain scans are not used as a diagnostic tool
• therefore, the explanation may be a result of sz, not a cause of the disorder
• therefore making research less valid and credible.