Biological explanation to explaining schizo

Question 1

What are the genetic explanations for schizophrenia

Answer 1

family studies and Twin studies

Question 2

Family study

Answer 2

Gottesman et al
Family studies has shown that schizophrenia is more common among biological relatives of a person with schizophrenia. The closer the degree of genetic relatedness, the greater the risk.

Gottesman found children with two schizophrenic parents had a concordance rate of 46% and 13% with just one schizophrenic parent. Siblings had a 9%

Question 3

Twin studies

Answer 3

Joseph showed that concordance rate for MZ twins was 40.4% and 7.4% fro DZ twins

In Gottesman study 48% of twins had concordance rate while 17% of fraternal twins had schizophrenia

Question 4

Dopamine hypothesis

Answer 4

Excess of neurotransimittter dopamine in certain areas of the brain is associated with the positive symptoms of schizophrenia

Schizophrenics are thought to have high number of D2 receptors which results in more dopamine binding and stimulating and therefore more neurones firing

Question 5

What are the two sources of evidence that support the dopamine hypothesis

Answer 5

1) drugs that increase dopaminergic activity

2) Drugs that decrease dopaminergic activity

Question 6

drugs that increase dopaminergic activity

Answer 6

Amphetamines is a dopamine agonist which causes the flooding of dopamine. Normal individuals that are exposed to high levels of dopamine tend to experiences positive symptoms of schizophrenic episode.

Question 7

Drugs that decrease dopaminergic activity

Answer 7

Antipsychotic drugs (antagonists) block the activity of dopamine. Reduces activity of dopamine so eliminate symptoms such as hallucinations and delusions.

Question 8

Neural correlates

Answer 8

Measurements of the structure or function of the brain that correlate with an experience of schizophrenia. Both Positive and negative symptoms gave neural correlates.

Question 9

Neural correlates of negative symptoms

Answer 9

Avolition= loss of motivation.
Motivation involves the anticipation of a reward and certain regions of the brain e.g. ventral striatum. Juckel et al measured activity levels in the ventral striatum in schizophrenics and found lower levels of activity than those of the control group. They found a negative correlation between activity levels in the ventral striatum and the severity of overall negative symptoms.

Question 10

Neural correlates of positive symptoms

Answer 10

Allen et al scanned the brains of people experiencing auditory hallucinations and compared them to a control group whilst identifying pre recorded speech of theirs or others. Lower activation levels in the superior temporal gyrus and anterior cingulate gyrus were found in the hallucination group who also made more errors than control group.

Reduced activity of these two areas is a neural correlate of auditory hallucination.