The Biological Explanation of Schizophrenia (Clinical Psychology)

Question 1

What is the Dopamine Hypothesis for Schizophrenia?

Answer 1

People with sz have higher levels of dopamine in the synapses of the neurones in their brains. Raised levels can be caused by increased release into the synapse.

People with sz may also have increased sensitivity to dopamine

Question 2

Increased dopamine in what areas of the Brain are linked to what Symptoms of Schizophrenia?

Answer 2

Increased dopamine in:

• Mesolimbic pathway (mid brain) = Positive Symptoms
• Mesocortical pathway (frontal lobe) = Negative Symptoms (Give examples of symptoms)

Question 3

What is the Glutamate Hypothesis for Schizophrenia?

Answer 3

Research suggests there are strong links between low levels of glutamate and psychotic symptoms including schizophrenia

Question 4

What research evidence supports the biological explanation of schizophrenia?

Answer 4

Randrup + Munkvad, Lieberman

Question 5

What did Randrup and Munkvad find in support of the biological explanation of schizophrenia, and what was a problem with the study?

Answer 5

They injected rats with amphetamine, which raises dopamine levels. The rats became more aggressive and isolated. These are similar symptoms to schizophrenia. - Animal studies aren’t generalisable to humans

Question 6

What did Lieberman find which supports the biological explanation of schizophrenia, and what was a problem with the study?

Answer 6

75% of those with schizophrenia experienced further symptoms or psychotic episodes after taking dopamine imitators, like amphetamines and methylphenidate - The patients already had schizophrenia, so they won’t vulnerable to the effects of dopamine. This doesn’t necessarily mean that it caused the disorder.

Question 7

What drug research supports the biological explanation of schizophrenia?

Answer 7

Amphetamines are dopamine agonists which can cause amphetamine psychosis, which has symptoms similar to positive symptoms of schizophrenia - However it doesn’t show why negative symptoms occur

Question 8

What is an Alternative Theory to the biological explanation of schizophrenia?

Answer 8

Some genes are associated with dopamine production and sensitivity are found more in those with schizophrenia. It may be that genes are the cause, rather than the dopamine

Question 9

What Gene is known to possibly link to Schizophrenia?

Answer 9

C4 C4 is the for pruning. Excessive pruning can lead to positive symptoms, like hallucinations + delusions. Therefore C4 can possibly lead to schizophrenia

Question 10

What is Pruning?

Answer 10

Pruning is when the brain gets rid of information that’s deemed of not being important

Question 11

What is the Genetic Hypothesis for Schizophrenia?

Answer 11

The more closely related to family member to the individual with schizophrenia, the higher the chances of developing the disorder

Question 12

What is the Genetic Risk of getting schizophrenia for the General Population?

Answer 12

1%

Question 13

What is the Genetic Risk of getting schizophrenia with a Second Degree Relative having it?

Answer 13

2.5%

Question 14

What is the Genetic Risk of getting schizophrenia with a First Degree Relative having it?

Answer 14

Parent: 3.8% Sibling: 8.7% One Parent: 8.7% Two Parents: 12%

Question 15

What is the Genetic Risk of getting schizophrenia with a DZ twin or MZ twin having it?

Answer 15

DZ Twin: 30-40% MZ Twin: 40-50%

Question 16

What Research Evidence supports the genetic explanation of schizophrenia?

Answer 16

Gottesman, Tienari, Gottesman’s Family studies

Question 17

How does Gottesman’s study Support the genetic explanation of schizophrenia?

Answer 17

Gottesman’s 1991 analysis of twin studies revealed:

• 48% concordance for MZ twins
• Only 17% concordance for DZ twins.

Also reported that the concordance rate for identical twins brought up apart was very similar to that for identical twins brought up together

• • However, critics have argued that the twins did not spend all of their childhood apart.

Question 18

How does Tienari’s study Support the genetic explanation of schizophrenia?

Answer 18

10.3% of adopted children who had a schizophrenic mother developed schizophrenia.

Only 1.1% of adopted children who did not have a schizophrenic mother developed it

Question 19

How does Gottesman’s family studies Support the genetic explanation of schizophrenia?

Answer 19

The risk of developing schizophrenia more closely related to the schizophrenic.

• If both parents have schizophrenia = 46% chance
• One schizophrenic parent = 16% chance
• A schizophrenic sibling = 8% chance

Question 20

What research evidence Challenges the genetic explanation of schizophrenia?

Answer 20

Torrey, Wahlberg, Joseph

Question 21

How does Torrey’s study Challenge the genetic explanation of schizophrenia?

Answer 21

Torrey argued that many twin studies were inadequate due to small samples and biased allocation of twins and fraternal. (There weren’t equal amounts of MZ and DZ twins).

He reviewed eight studies with representative samples and a reasonably certain allocation of twins and found:

• Concordance rate of 28% for MZ twins and 6% for DZ twins.

Similarly Joseph 2003 reported from nine studies, finding:

• Concordance rate of 22.4% for MZ and 4.6% for DZ twins.

This shows that when twins aren’t cherry picked, there is a lower concordance rate.

Question 22

How does Wahlberg’s study Challenge the genetic explanation of schizophrenia?

Answer 22

Wahlberg reported additional findings from the study started by Tienari, which show that environmental factors are important. They found the genetic risk of schizophrenia increased significantly if the adoptive family was high in communication deviance (tendency to communicate in unclear and confusing ways

Question 23

What Evidence suggests that schizophrenia due to the Environment, rather than Genes?

Answer 23

The higher concordance rate in MZ twins may be due to the fact that MZ twins tend to be more treated more similarly than DZ twins Fewer than 50% of children where both parents have schizophrenia developed the order

Question 24

How does Joseph’s study Challenge the genetic explanation of schizophrenia?

Answer 24

The fact that concordance rate increase with genetic relatedness may be because they’re also likely to spend more time together, meaning environmental factors may be influential. Joseph found higher concordance is in fraternal twins than ordinary siblings.

Question 25

What Evidence suggests that schizophrenia due to Our Biology, rather than Genes?

Answer 25

Throughout all countries, 1% of people are at risk developing schizophrenia Therefore without any genetic influence, you could still develop schizophrenia

Question 26

What is the Neuroanatomical Theory of Schizophrenia?

Answer 26

A lot of research has found that individuals with schizophrenia have enlarged ventricles in the brain

Question 27

Which schizophrenic symptoms are enlarged ventricles associated with?

Answer 27

Enlarged ventricles almost associated with negative symptoms of schizophrenia, and also with patients who have the worst outcomes.

Question 28

What research evidence supports the neuroanatomical theory of schizophrenia?

Answer 28

Johnstone et al: Compared the CAT scans of schizophrenic patients, and matched controls. They found that those with schizophrenia had significant enlargement in ventricular areas. Giedd et al: Found that patients with early onset schizophrenia showed significant developmental increase in ventricular size throughout a longitudinals study

Question 29

What Criticism is there for the Neuroanatomical Theory of Schizophrenia?

Answer 29

It is difficult to identify the cause and effect relationship, as brain abnormality rather than the cause of the illness