Schizophrenia: The Neurodevelopmental Hypothesis

Question 1

Why do we look at brain structure as a factor in development of schizophrenia?

Answer 1

Because there has been much evidence to suggest that brain structure is different in schizophrenia patients compared to a healthy person.

Question 2

What did Crow (1985) conclude about brain structure and symptoms of schizophrenia?

Answer 2

That positive symptoms are best explained by neurotransmitters and negative symptoms are best explained by brain structure.

Question 3

List the 3 elements of brain structure as a biological explanation for schizophrenia.

Answer 3

1) Enlarged ventricles
2) Damaged frontal lobes
3) Loss of grey matter

Question 4

Define ‘ventricles’.

Answer 4

Centres of the brain that contain spinal fluid and supply blood and oxygen to densely packed neurons.

Question 5

How do ventricles explain the cause of schizophrenia?

Answer 5

They have smaller brains and larger ventricles which causes a thinning of the cerebral lining. Enlarged ventricles is usually due to underdevelopment in some areas or loss of brain cells that causes fluid to fill the empty space.

Question 6

State a statistic about schizophrenic patients and enlarged ventricles.

Answer 6

Approximately 25% of patients with schizophrenia have enlarged ventricles.

Question 7

Which areas of the brain are said to be a potential factor in causing schizophrenia?

Answer 7

The frontal lobes.

Question 8

How does damage to the frontal lobes explain the cause of schizophrenia?

Answer 8

Catatonia and speech arrest are common negative symptoms for schizophrenic patients and those that suffer from brain damage. Brian imaging techniques have shown that low level of activity in the frontal lobe is similar to those with frontal lobe damage when performing a car sorting task.

Question 9

Why does the onset of schizophrenia seem to be most common in adolescence?

Answer 9

The prefrontal cortex develops through adolescence and so if it is damaged prior, the effects would only become known during young adulthood whereby schizophrenia is most commonly diagnosed.

Question 10

What is grey matter in the brain?

Answer 10

Darker tissue that consists of nerve cells and dendrites.

Question 11

How does loss of grey matter explain the cause of schizophrenia?

Answer 11

Patients who have never been treated for their schizophrenia show a reduced volume of grey matter, especially in the frontal lobe. Damage starts in the outer regions of the brain and spreads to the rest over a 5 year period and those with the worst tissue loos show the worst symptoms.

Question 12

State a statistic about schizophrenic patients and loss of grey matter.

Answer 12

There is a grey matter loss of up to 25% in patients with schizophrenia.

Question 13

What factor is said to cause this brain damage?

Answer 13

Exposure to viruses/brain damage as a fetus.

Question 14

What did Cantor-Graae et al (1994) find in terms of difficulties during birth and schizophrenia?

Answer 14

He found that difficulties during birth is more likely to result in schizophrenia in those who do no have a family history of the disease.

Question 15

Give an example of a virus that has been seen to lead to schizophrenia if exposed to it in the womb.

Answer 15

People who were exposed to the influenza virus during the second trimester of their fetal development were more likely to develop schizophrenia.

Question 16

What did Murray (1997) find in terms of difficulties during birth and schizophrenia?

Answer 16

He reviewed studies of birth difficulties, such as premature babies and oxygen starvation, and found that 7/8 developed schizophrenia.

Question 17

How could damage to the prefrontal cortex in the womb link to onset of schizophrenia?

Answer 17

Damage to the frontal lobes is correlated with developing schizophrenia and so any damage as a child would not be seen until it develops through adolescence whereby any damage would become prevalent.

Question 18

How might dopamine activity also link to onset of schizophrenia?

Answer 18

Dopamine activity peaks in adolescence and due to its over-activity being correlated with developing schizophrenia, it would be more likely diagnosed during this time.

Question 19

Using the acronym ‘EACH’, evaluate 2 ‘evidence’ points.

Answer 19

P - Research into grey matter supports
E - Evidence shows schizophrenic patients and those with frontal lobe damage show the same levels of low activity in their frontal lobe when performing card tasks
E - This therefore supports the idea that damage to the prefrontal cortex could result in schizophrenia
P - Murray (1997) supports
E - He found that 7/8 studies of schizophrenic patients had difficulties during birth such as premature and oxygen starvation
E - This therefore supports the idea that brain damage during a fetus may lead to the development of schizophrenia in later life

Question 20

Using the acronym ‘EACH’, evaluate 2 ‘how’ points.

Answer 20

P - Research is reliable
E - CAT scans are highly objective and scientific
E - Therefore meaning comparisons are easier to make
P - Research is carried out on animals
E - Animal brains are different to humans due to qualitative differences from being less complex
E - Therefore research wouldn’t fully represent the brains of humans and so makes findings less credible and generalisable

Question 21

Are there any applications?

Answer 21

P - Yes
E - This theory suggest that schizophrenia could be caused by loss of grey matter, enlarged ventricles, and damage to the prefrontal cortex
E - Therefore research could be done into reversing these effects or stabilising them so that they don’t get worse

Question 22

Using the acronym ‘EACH’, evaluate 2 ‘criticisms’ points.

Answer 22

P - Cannot establish cause and effect
E - Due to research only taking place after onset it is hard to distinguish if changes in brain structure causes the disorder or is an effect of it
E - Therefore making research less valid and credible
P - Reductionist
E - It states that schizophrenia is down to brain damage occurring biologically
E - Therefore disregarding environmental factors that may influence brain damage such as TBI or simply influence development of schizophrenia in other ways