Theories on the Causes

Question 1

What are the theories?

Answer 1

The early neurodevelopmental model
The late neurodevelopmental model
Two hit model

Question 2

What is the early neurodevelopmental model?

Answer 2

There are fixed lesions / early trauma which occur early on in life, in gestation which lies in the brain till further maturation of the brain, till the brain is sufficient to call into operation the damaged systems - explains why disorder is diagnosed in early adulthood

Question 3

What is the evidence for abnormal brain development?

Answer 3

Home movies from families with schizophrenic children - independent observers examined the behaviour of the children. those who became schizophrenic displayed more negative affect in their facial expressions and more likely to do abnormal movements

danish children aged 11-13 years, were videotaped while eating lunch. blind raters found that the children who later got schizophrenia displayed less sociability and deficient psychomotor functioning

Question 4

What evidence supports the early neurodevelopmental theory?

Answer 4

Home observations of children when younger - displaying negative symptoms

Physical abnormalities

Question 5

How do physical abnormalities impact people?

Answer 5

Minor abnormalities, such as widest or narrow eyes, are associated - people with schizo relatives normally have a 12% chance of developing it but this increases to 31% in people who have minor physical anomalies

Question 6

What are the physical abnormalities?

Answer 6

Bigger head
Wide eyes
Low seated eats
Furrowed tounge
Curved fifth finger
Third toe longer than second

Question 7

What is the late neurodevelopmental model?

Answer 7

Schizophrenia may result from an abnormality in adolescence when synaptic pruning takes place - period of reorganisation, going wrong

Question 8

What is the two hit model?

Answer 8

Abnormal development in schizophrenia takes place during 2 critical time point
early developmental events may lead to dysfunction of specific neural networks that would account for premorbid signs
during adolescence, excessive synaptic pruning and loss of plasticity may account for emergence of symptoms

Question 9

What is the evidence of developmental pruning?

Answer 9

In a normal brain, have a normal amount of developmental pruning
Much greater if you have schizophrenia, 3/4% is synaptic pruning

Question 10

What leads to the onset in adulthood?

Answer 10

Many processes which take place early on

Question 11

When is the disease shown?

Answer 11

Males - 20-28

Females - 26-32

Question 12

What causes the disease to occur?

Answer 12

Birth
Genes - susceptibility genes interacting with the environment
Adolescence
= schizophrenia

Question 13

What are the birth problems?

Answer 13

Obstetric complications
Prenatal infection
Nutritional deficiency

Question 14

What are the problems in adolescence?

Answer 14

Adverse life events

Substance use - 6X more likely to get schizophrenia if smoke weed

Question 15

What are the structural changes in the brain?

Answer 15

Enlarged ventricles - even if identical twins, means that cells are dying out so bigger holes

Reduced brain volume / less grey matter in temporal and frontal lobes and hippocampas

Faulty cellular arrangement in the cortex and hippocampus - disorganised

Question 16

Is there evidence for structural changes?

Answer 16

Weinberger and Wyatt - CT scans of 80 schizophrenics and 66 healthy controls of the same mean age and measured the lateral ventricles. the size of the ventricles of the patients was more than twice as big as normal subjects